Step 1

Preheat the oven to 400° F.

Step 2

Place eggs, heavy cream, whole milk, and the Dijon into the barrel of a food processor. Pulse 8 to 10 times or until eggs are frothy and ingredients are well incorporated. Add salt and pepper and pulse 2 more times.

Step 3

Add butter to a heavy cast iron or other oven-proof skillet over medium heat. Add the leeks and the red onion and sauté until soft, about 3 minutes. Add the shallot and sauté 1 minutes more. Remove the skillet from the heat.

Step 4

Using a metal spatula, loosen the leeks and onions and shallot is there is any sticking.

Step 5

Scatter the chives, half the dill, any add-ins (I am using leftover hash brown potatoes which I have brought to room temperature), the smoked salmon, the cream cheese cubes, and half the capers.

Step 6

Pour the egg mixture over the salmon and other ingredients in the skillet. Top with the crumbled goat cheese.

Step 7

Cook for 3 minutes over medium heat, undisturbed. Avoid the urge to move or stir the eggs in any way. Carefully transfer the skillet to the preheated oven.

Step 8

Bake until the top is golden brown and the frittata is set; about 35 minutes. Cool for 5 minutes, then garnish with the remaining torn dill. Cut and serve warm.