Preheat oven to 350 degrees. Grease an 8 x 8 metal baking pan then line with parchment paper.
Add melted butter to a large bowl then whisk in brown sugar until well combined.
Whisk in egg until combined then add vanilla.
Add salt, baking powder and flour, stirring with a wooden spoon until just combined and flour streaks are still visible. Avoid overmixing.
Pour batter into prepared baking tin then smooth with a spatula.
Bake for 17 to 20 minutes until a toothpick inserted into the center yields a few moist crumbs. Do not overbake.
Remove pan from oven and immediately top with M&M Easter Eggs. Gently press candy eggs into the top of the blondies.
Place pan on a wire rack to cool completely, then use parchment to lift out. Cut blondies into squares and serve.
Blondies will keep at room temperature in an airtight container for 3 days.
