Caramelized fennel, pools of melted fresh mozzarella, and perfectly set eggs — all from one skillet in under 30 minutes. The fennel turns sweet and silky as it cooks down in olive oil and butter, then thick slabs of mozzarella melt into it while eggs gently set on top. A drizzle of lemon-Parmesan oil pulls the whole thing together with a brightness that cuts right through the richness. This is the kind of Italian breakfast that makes you slow down, pour another coffee, and actually enjoy your morning.

Each serving delivers 63 grams of fat and only 8 grams of net carbs, which lands squarely in keto territory. The 38 grams of protein come from a generous portion of eggs and a full three ounces of fresh mozzarella per person. Fat accounts for roughly 75 percent of total calories here, exactly where you want to be on a well-formulated ketogenic diet.

Beyond the macros, the beauty of this recipe is its simplicity. One skillet, eight ingredients you probably already have, and less than half an hour from cold pan to table. It reheats well for the next morning, scales up easily for a weekend brunch, and looks far more impressive than the effort it takes to pull together.

Ingredients (serves 2)

For the skillet:

  • 6 large eggs
  • 6 oz (170g) fresh mozzarella, torn into rough 1-inch pieces
  • 1 small fennel bulb (about 5 oz / 150g trimmed weight), thinly sliced, fronds reserved
  • 2 tbsp (30ml) extra-virgin olive oil
  • 1 tbsp (14g) unsalted butter
  • 2 cloves garlic, thinly sliced
  • Pinch of red pepper flakes
  • Salt and freshly ground black pepper

For the lemon-Parmesan oil:

  • 1 tbsp (15ml) extra-virgin olive oil
  • 2 tbsp (10g) finely grated Parmesan
  • 1 tsp lemon zest
  • 1 tbsp (15ml) fresh lemon juice
  • Fresh basil leaves, for serving

Instructions

  1. Prepare the fennel. Trim the fennel bulb, removing the tough outer layer and the stalks. Save any feathery fronds for garnish. Halve the bulb lengthwise, cut out the core, and slice each half into thin half-moons, about ⅛ inch (3mm) thick.

  2. Caramelize the fennel. Heat 2 tablespoons of olive oil and the butter in a 10-inch (25cm) oven-safe or lidded skillet over medium heat. Once the butter foams, add the sliced fennel in a single layer and season with a generous pinch of salt and a few grinds of black pepper. Cook for 8 to 10 minutes, stirring every couple of minutes, until the fennel is soft, golden at the edges, and noticeably sweet.

  3. Add the garlic. Push the fennel to the edges of the skillet and drop the sliced garlic into the center along with the red pepper flakes. Cook for about 45 seconds, stirring the garlic constantly, until fragrant but not browned. Toss the garlic through the fennel and spread everything into an even layer across the pan.

  4. Layer the mozzarella. Reduce the heat to medium-low. Scatter the torn mozzarella pieces evenly over the fennel. Let the cheese sit undisturbed for about 1 minute so it begins to soften against the hot fennel.

  5. Crack in the eggs. Using the back of a spoon, make 6 small wells in the fennel-mozzarella layer. Crack one egg into each well. Season the eggs lightly with salt and pepper. Cover the skillet with a lid or a sheet of aluminum foil.

  6. Cook until set. Let the eggs cook covered over medium-low heat for 6 to 8 minutes. Check at 6 minutes — the whites should be fully set and opaque, while the yolks remain soft and runny. If you prefer firmer yolks, continue cooking for another 1 to 2 minutes. The mozzarella will be fully melted and bubbling gently around the eggs.

  7. Make the lemon-Parmesan oil. While the eggs cook, stir together 1 tablespoon of olive oil, the grated Parmesan, lemon zest, and lemon juice in a small bowl. It will form a loose, slightly grainy drizzle.

  8. Finish and serve. Remove the skillet from the heat. Spoon the lemon-Parmesan oil over the eggs in a zigzag pattern. Tear a few basil leaves over the top and scatter the reserved fennel fronds. Serve immediately, straight from the skillet, with spoons or a spatula to scoop out individual portions.

Nutrition per Serving

Nutrient Amount
Calories ~745 kcal
Fat ~63g
Protein ~38g
Total Carbs ~10g
Fiber ~2g
Net Carbs ~8g

Nutrition values are approximate and based on standard USDA data for the ingredients listed.

Tips & Variations

Choose the right mozzarella. Fresh mozzarella packed in water (the soft, milky kind sold in balls) is what you want here. It melts into creamy pockets that mix with the fennel beautifully. Low-moisture shredded mozzarella will work in a pinch, but the texture becomes more rubbery and stringy rather than lush. If your market carries burrata, use it instead — split it open over the finished dish right before serving for an absurdly rich upgrade.

Watch for hidden carbs in pre-shredded cheese. Bagged shredded cheese often contains potato starch or cellulose as anti-caking agents, which adds a gram or two of carbs per serving that are not always reflected accurately on the label. For keto precision, buy blocks or balls and shred or tear them yourself. This recipe keeps net carbs at 8 grams, and that number assumes no fillers in the cheese.

Swap the fennel for other low-carb Italian vegetables. If fennel is not available or not your thing, try thinly sliced zucchini rounds, baby spinach (add it right before the mozzarella since it wilts fast), or halved cherry tomatoes (use only 4 to 5 to keep carbs down). Each swap will change the flavor profile but the cooking method stays the same. Avoid bell peppers in large quantities — they carry more sugar than most people expect.

Store and reheat for a second breakfast. Leftovers keep in an airtight container in the fridge for up to 2 days. Reheat gently in a covered skillet over low heat for 4 to 5 minutes, or in a 300°F (150°C) oven for about 8 minutes. The yolks will set fully during reheating, so if you like runny yolks, this is best eaten fresh. The flavor actually deepens overnight as the fennel and lemon oil meld together.

Make it heartier without adding carbs. Lay a few slices of avocado alongside each serving for extra fat and creaminess. You could also scatter toasted pine nuts over the finished dish — about 1 tablespoon per serving adds 3 grams of fat and less than 1 gram of net carbs. A spoonful of pesto on the side works too, but check store-bought pesto labels since many brands add sugar or cheap fillers.

Frequently Asked Questions

Is fennel keto-friendly?
Yes, fennel is a solid choice for keto. A small bulb (about 150 grams trimmed) contains roughly 11 grams of total carbs and nearly 5 grams of fiber, bringing the net carbs to around 6 grams for the entire bulb. Split between two servings, that is only 3 grams of net carbs per plate from the fennel alone. It also brings a natural sweetness that develops as it caramelizes, so it satisfies without any added sugar. Compare that to onions, which pack about twice the net carbs per gram, and fennel starts looking like an underrated keto vegetable.
Can I use a different cheese instead of mozzarella?
You can, though the character of the dish will change. Fontina melts similarly to mozzarella and adds a nuttier, earthier flavor that pairs well with fennel. Gruyère works if you want something more assertive. Goat cheese crumbles are another option — they will not melt into stretchy pools but instead soften into tangy dollops. Avoid very hard cheeses like aged Parmesan as your main cheese since they do not melt the same way and will not create that creamy layer around the eggs. You can always keep the Parmesan in the finishing oil regardless of which melting cheese you pick.
How do I store and reheat leftovers?
Let the skillet cool to room temperature, then transfer individual portions to airtight containers. Refrigerate for up to 2 days. To reheat, place a portion in a small skillet with a splash of water, cover, and warm over low heat for 4 to 5 minutes until heated through. The microwave works in 30-second bursts at medium power, but the cheese texture suffers a bit. The egg yolks will firm up during storage no matter what — that is unavoidable. For batch-prepping, consider slightly undercooking the eggs on the first go so they finish setting during the reheat.
How can I make this dairy-free or vegan keto?
Dairy-free keto is trickier here since mozzarella is the star. Your best bet is a cashew-based or coconut-based mozzarella alternative — brands like Miyoko's or Violife melt reasonably well, though the flavor will not be identical. Skip the butter and use all olive oil instead. For the finishing drizzle, replace the Parmesan with nutritional yeast (about 1 tablespoon) mixed with the lemon and oil. To make it fully vegan, swap the eggs for firm tofu sliced into thick rounds, seared until golden, then nestled into the fennel. The macros will shift, so recalculate if you are tracking closely.
Why are my eggs cooking unevenly in the skillet?
This usually comes down to heat distribution or uneven wells in the fennel layer. Before cracking the eggs, make sure the fennel and mozzarella are spread evenly across the pan — any bare spots on the skillet surface will cook the egg white faster than areas cushioned by fennel. Keep the heat at medium-low, not medium. If your skillet has a known hot spot (common with thinner pans), rotate it 180 degrees halfway through cooking. A well-seasoned cast iron skillet holds steady, even heat better than most nonstick pans and is the ideal choice for this recipe.