Blanch the red peppers in boiling salted water for 2 minutes. Drain on paper towel until cool. Blanch the spinach 30 seconds or until bright green and wilted. Drain on paper towels until cool. Transfer the peppers to a rimmed baking sheet. Whisk eggs, milk, onions, garlic, salt and pepper. Set aside.

Then divide the spinach among peppers. Pour an equal amount of egg mixture in each pepper. Place peppers on baking sheet sprayed. BAKE 350 for 20 minutes. Sprinkle cheese over peppers, bake for 10 minutes or until egg is set and cheese is melted.