Muffin Tin Low Carb Breakfast Casserole

Ground breakfast sausage (1 lb)

Garlic (minced, 1 tbsp)

Bell peppers (diced, 2 cups)

Yellow onion (diced, 1/2 cup)

Spinach (chopped, 3 cups)

Eggs (12)

Salt and pepper (to taste (I used about 1/8 tsp each))

Cheddar cheese (shredded, 1/2 cup)