Preheat oven to 375 degrees F.
Melt cooking fat in a skillet. Add the shredded potatoes and saute over medium-high heat for about 3 minutes.
Cooking fat, 2 russet or sweet potatoes
Cover and cook over medium-low heat for another 3 minutes, then place in a layer at the bottom of the baking dish.
Add more cooking fat to the skillet; cook the onion and garlic for 2 to 3 minutes.
1 onion, 2 garlic cloves
Add the bell pepper and sliced mushrooms; cook until soft, 4 to 5 minutes.
1 bell pepper, 1 cup mushrooms
Add in the fresh spinach and tomatoes for the last 2 minutes.
1 cup fresh spinach, ½ cup grape tomatoes
Remove from heat and place the veggies on top of the shredded potatoes.
In a large bowl, whisk together the eggs and season to taste.
12 eggs, Sea salt and freshly ground black pepper
Pour the egg mixture over the vegetable-filled baking dish, then place it in the oven.
Bake for 40 to 45 minutes.