- Preheat oven to 350F. Brush soft butter over the bottom and sides of each tin in a 6-cup muffin pan. Distribute the parmesan evenly between the 6 cups, then jiggle the pan side to side to spread the cheese around as much of the surface as possible, it will stick to the buttered surface. (If any cheese doesn’t stick, just leave it in the bottom.) Set aside.
- Heat the oil in a small saute pan over medium-high heat. Add the onion and a sprinkling of salt and cook until the onion is a light golden brown. Add the vegetables to the pan and cook until warmed through. Remove pan from heat.
- In a large mixing bowl, whisk the eggs until well-blended. Stir in the vegetables and cheese, adding salt and pepper to taste. Distribute the mixture evenly among the six muffin tins. Place in oven and bake until puffed and golden, 15-20 minutes. Serve while warm.