Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking pan by greasing or lining it with parchment paper.

Melt ½ cup of unsalted butter over low heat in a medium saucepan, stirring occasionally until liquid and glossy.

Stir in ¾ cup of light brown sugar and ½ cup of granulated sugar until fully combined.

Whisk in 2 room-temperature eggs, one at a time, then add 1 teaspoon of pure vanilla extract.

Sift together 1 ½ cups of all-purpose flour, 1 teaspoon of baking powder, and a pinch of salt in a separate bowl.

Gently fold the dry mixture into the wet ingredients until just combined.

Fold in 1 cup of chopped Mini Cadbury Eggs gently until evenly distributed in the batter.

Pour the batter into the prepared baking pan and bake for 25-30 minutes until a toothpick comes out with moist crumbs.

Allow the blondies to cool in the pan for at least 15-20 minutes before lifting out and slicing into squares.