Preheat oven to 375°F.
In a large bowl, whisk together eggs, milk, cream, salt, and pepper then add cheese and stir until mostly smooth.
Roll out the puff pastry to fit your baking dish (I used a 9" tart pan). Press dough against the sides and remove the excess dough.
Spread leeks across the bottom of the dough, top with the salmon and then pour the egg mixture over the top. Sprinkle dill on top.
Bake for 30-40 minutes, until the center is firm and the crust is golden brown.
6 servings