Preheat oven to 350 degrees. Whisk egg, cream, salt, and pepper together in a separate bowl. Set aside.
In a 10" ovenproof skillet over medium-high heat, saute onions and zucchini until soft. Add spinach and stir until wilted.
Reduce heat to medium and add smoked salmon, herbs, and gouda to the skillet.
Pour egg and cream mixture over the top. Continue cooking until the frittata begins to pull away from the sides of the pan, 5 to 7 minutes.
Remove from heat and place in oven. Bake for 16 to 18 minutes, or until the center is set.
Delicious topped with a dollop of sour cream, fresh herbs, and even some more cheese.
Kori's Tips
You can easily substitute dried herbs for fresh ones. If using dried herbs it works best to whisk them in the egg and milk mixture first.Cooked asparagus makes a great substitution in this recipe!Feel free too experiment with different meats and cheeses. Bacon or sausage is an easy swap for smoked salmon!