Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with aluminum foil, leaving some overhang for easy removal, and spray it lightly with cooking spray.

In a microwave-safe bowl, melt 1 cup of unsalted butter for about 30-40 seconds until it’s just melted but not bubbling. Allow it to cool slightly before adding in one large egg, 1 cup of light brown sugar, and 1 teaspoon of vanilla extract. Whisk the mixture until smooth and creamy.

Gently add 1 cup of all-purpose flour and a pinch of salt into your butter mixture. Stir until just combined.

Carefully fold in 3/4 cup of M&M's Milk Chocolate Eggs into the blondie batter.

Pour the blondie batter into your prepared baking pan, using a spatula to spread it evenly. Sprinkle the remaining 1/4 cup of M&M's Eggs on top.

Place the pan in the preheated oven and bake for about 20 minutes.

Once baked, remove the pan from the oven and let the blondies cool in the pan for about 30 minutes before slicing into squares.