Prep your workspace. Line a 9x13 baking pan or rimmed baking sheet with wax paper or parchment paper, leaving some overhang on the sides for easy removal later. Spray lightly with cooking spray.
Melt the butter. In a large pot over low heat, melt the butter, being careful not to let it brown. If using a microwave, place butter in a large microwave-safe bowl and heat for 30-45 seconds until melted.
Add the marshmallows. Add marshmallows to the melted butter and stir continuously over low heat until completely melted and smooth. If using a microwave, heat in 30-second intervals, stirring between each, until smooth. This usually takes about 1.5-2 minutes total.
Add flavor boosters. Remove from heat and stir in vanilla extract and salt.
Decision time: Single color or rainbow?- For a single color batch: Add food coloring to the melted marshmallow mixture until you reach your desired shade. Remember that the color will lighten slightly when you add the cereal.- For multiple colors: Divide the marshmallow mixture equally into separate bowls (one for each color you want) and add different food coloring to each. Add the cereal. Fold in the Rice Krispies cereal, stirring gently until all the cereal is evenly coated. Try not to crush the cereal as you mix.
Press into pan. Transfer the mixture to your prepared pan. Using a piece of wax paper or a spatula sprayed with cooking spray (to prevent sticking), press the mixture evenly into the pan, about 1/2 inch thick.
Cool slightly. Let the treats cool for about 10 minutes until they're still pliable but not too sticky.
Cut into egg shapes. Using your Easter egg cookie cutter, firmly press down to cut out egg shapes. To prevent sticking, you can dip the cookie cutter in a little water or spray it with cooking spray between cuts.
Maximize your yield. Try to cut the eggs as close together as possible to minimize waste. (Though let's be honest, those scraps are the chef's treat!)
Decorate if desired. If adding decorations:- For chocolate drizzle: Melt white chocolate chips or candy melts and drizzle over eggs using a fork or spoon.- For sprinkles: Add immediately after drizzling while chocolate is still wet.- For icing designs: Mix powdered sugar with milk until smooth, place in a small plastic bag, snip the corner, and pipe designs Set completely. Allow the treats to cool completely on wax paper, about 30 minutes, until firm and the decorations have set.
Store properly. Place in an airtight container with wax paper between layers for up to 3 days, though they're best enjoyed within 2 days for maximum freshness.