Preheat oven to 350°F (175°C).

In a large bowl, whisk eggs together until slightly foamy.

Stir in the almond flour and baking powder.

In a large sauté pan, melt the butter, then add in the onions and spinach, cooking until onions are translucent.

Mix in the peppers and any other vegetables of your choosing.

Stir the veggie/butter mixture into the eggs, and pour the contents into a 9 inch x 13 inch (23 cm x 33 cm) baking dish, and top with pepper.

Bake for 45 minutes or until cooked through.