Modified to create two single serving frittatas.
Heat the oven to 400 degrees F. Place the skillets each on a burner on the stove. Add a drizzle of olive oil on the bottom of each skillet and turn on the burners to medium heat.
Add spinach and roasted bell peppers/sun dried tomatoes to the skillets. Saut̮̩̉̉ to remove extra liquid.
Put the egg whites in one bowl and the egg yolks in the other. Divide the milk, garlic powder, salt and pepper amongst both bowls and whisk until combined.
Pour the egg mixture in the warm skillets. Add the cheese on top. Place the warm skillet in the oven for 15 minutes (until the edges are browned and the center is cooked.
Pull the skillets out of the oven. Use the spoonula to scrape around the edges of the frittata. You should be able to invert the skillet on the plate to serve.