18 large eggs
1/3 cup milk or cream
1-1/2 tsp olive oil
1-1/2 cups broccoli florets, diced
1/2 red bell pepper, minced
1 small red onion, minced
1 Tbsp thyme leaf
Kosher salt and fresh ground black pepper, to taste (be generous; if the frittata will be served cold, you'll need to make sure it's well seasoned)
Pinch of red pepper flakes or a few shakes of hot sauce (optional)
2 cups coarsely grated cheddar or swiss cheese
Preheat oven to 325°F. Whip eggs and milk or cream in a bowl until well combined and frothy, and set aside.
In a small sauté pan, cook the broccoli, pepper and onion in olive oil for a few minutes, just until the onion is translucent. When the mixture has cooled, combine with the eggs and all remaining ingredients except the cooking spray.
Coat the inside of a bundt pan with cooking spray, and pour in the egg mixture. Place the bundt pan in a straight-sided roasting pan, and set on the oven rack. Fill halfway with hot tap water, and set into the oven (this is called a bain marie). Bake for one hour, until the eggs are set and slightly browned on top. Remove from oven, and remove bundt pan from the water. Let it rest for 5-10 minutes, then invert frittata onto a serving dish.