Chop about ½ cup of the mini eggs into small pieces.
Melt butter in a large non-stick saucepan over low heat.
Stir in marshmallows, and continue to stir until totally melted.
Turn off the heat and stir in Rice Krispies.
When most have been stirred in (and mixture has cooled slightly), stir in the chopped mini eggs.
Scrape mixture into prepared baking pan.
Use a spatula coated with cooking spray to press down gently into the pan.
Sprinkle with remaining mini eggs and press down gently.
Let cool for at least 30 minutes, then remove from pan and cut into squares.
Notes
Storage: Rice Krispie treats will store well for up to 3 days in an airtight container. Use waxed paper between layers of squares so that they don’t stick to each other. Don’t refrigerate these treats because they will harden and won’t soften up when brought to room temperature again. You can also freeze them for 4-6 weeks in a freezer bag or airtight container. Cut into squares before freezing. Let sit out at room temperature for about 15 minutes before eating, to allow them to soften up. Gluten-Free Note: Although Rice Krispies are made from rice, they also include malt syrup. Malt comes from barley and may contain gluten. That said, there are many other crispy rice cereals that do not contain gluten—look for “gluten free” on the packaging. Once you’re sure your crispy rice is gluten-free, you’re good to go, as the rest of the ingredients are gluten-free.