Spray Muffin Tin with Cooking Spray. |Dice up the bacon into small chunks and divide them evenly into each cup. place in the oven. You don't need to wait for your oven to preheat before getting the bacon in, you can put it in straight away.
While the bacon heats up/cooks: Dice and slice the vegetables. The smaller the better!Whisk the eggs, milk and salt/pepper together.Grate the cheese.
Once the bacon is sizzling, remove the muffin tin from the oven.
Divide all the vegetables into the muffin tins evenly and then pour the egg mixture on top. I like to start with filling each one half full and if there is some leftover you can top each one up. I find that using a liquid measuring cup is the best tool for this.
Bake for 20 minutes.
Run a rubber spatula or butter knife along the outside of each frittata muffin and serve.
To Make Ahead for Meal Prep
Store in an airtight container. Microwave for 30 seconds or until just heated through.