This Zucchini Frittata is a versatile dish that makes a great breakfast, lunch, or dinner. Incredibly delicious and creamy in texture, this Zucchini Frittata is undeniably the best. This is best served warm, room temperature, or even cold. If you serve it straight from the oven and it's too hot, you won't taste anything.
Place a rack in the upper third of the oven. Do not place the rack closest to the broiler but one below.
Heat oil and butter in a large 12” cast iron skillet or heavy nonstick oven proof skillet over medium high heat. A large nonstick saute pan also works.
Add the onions, zucchini, and some salt. Cook, stirring occasionally until zucchini is softened and moisture in the pan has mostly evaporated- about 8 - 10 minutes. You may have to lower the heat a bit if it gets too brown. Stir in garlic and cook until fragrant - about 1 minute.
Meanwhile, in a large bowl, add eggs and start to break them up with a whisk. Add 1 teaspoon of the salt, pepper, cream, and 1 cup of cheese. Beat until combined. Set aside.
Pour the egg mixture into the pan then remove from heat.
Bake for about 25 minutes until the top is just golden and set in the middle. Remove from the oven and sprinkle remaining cheeses over top.
Heat the broiler.
Place skillet on the upper third rack you set earlier. Broil for about 1 minute. The top should be lightly golden and the frittata puffed slightly. If not golden, broil for 30 seconds longer but keep an eye on it.
Remove from the oven and shake pan to loosen. Set on rack to cool and set. This needs to cool a bit in order for you to taste it. I serve it warm or room temperature. It's also delicious cold.
IMPORTANT: Place an oven mitt or kitchen towel over the skillet handle after removing it from the oven. I’m telling you from experience, it’s easy to forget the handle is hot and burn your hand.
*Scraping out the seeds is recommended if using a large zucchini. Simply slice the zucchini lengthwise and use a spoon to scrape out seeds.