Preheat your oven to 375 degrees F. Spray a 12-cup muffin tin generously with nonstick cooking spray, making sure to coat the sides of each cup not just the bottom. This is what keeps the cups from sticking when you pop them out.

If you have not already cooked your rice and steamed your broccoli, do that now and let both cool slightly. Chop the steamed broccoli florets into small pieces, roughly the size of a pea or a little larger. Big chunks will make the cups fall apart.

In a large mixing bowl, combine the cooked rice, chopped broccoli, shredded cheddar, beaten eggs, garlic powder, salt, and pepper. Stir everything together until the egg coats the mixture evenly and nothing is dry or clumping at the bottom.

Scoop the mixture into the prepared muffin cups, dividing it evenly among all 12. Each cup should be nearly full. Use the back of a spoon or your fingertips to press the mixture down firmly and compact it. This compression is what holds the cups together after baking, so do not skip it.

If using Parmesan, sprinkle a little over the top of each cup now for a slightly crispy, golden top.

Bake for 16 to 18 minutes, until the edges are visibly golden and the tops feel set when you press them lightly with a fingertip. The cheese should be melted and just starting to brown at the edges.

Remove from the oven and let the cups sit in the tin for 5 full minutes before attempting to remove them. Run a butter knife around the edge of each cup, then lift them out with a spoon or small offset spatula. They will hold together once they have had time to cool slightly and firm up.