Preheat the oven to 350°F/175°C and line an 8x8 inch pan with parchment paper and lightly grease.
In a small saucepan or microwave at 15 second intervals, melt the butter. Allow it to cool for 5-6 minutes.
1 cup butter
Pour into a bowl. Add in both sugars and whisk until well combined.
1 cup brown sugar, 1/3 cup white sugar
Add in eggs and vanilla. Whisk for 2-3 minutes until batter is light, glossy and smooth.
2 eggs, 1 tbsp vanilla
Switch to a spatula, and fold in the flour and baking powder. Mix until just combined.
2 cups all-purpose flour, 1 tsp baking powder
Gently fold in the creme eggs.
1 package Cookies n Creme eggs
Transfer to the prepared pan and spread evenly. Place into the oven to bake for 30-33 minutes. You'll want to start keeping a close eye at around the 28 mark.
For a chewy blondie, bake for 30 minutes. For a more cakey texture, keep baking for at least 35 minutes. If you'd like a more cakey texture, the blondies will most likely begin to brown at the top. Loosely cover the pan with aluminum foil on top.
Remove from oven and allow to cool completely. Drizzle with melted white chocolate. Place into fridge for 10 minutes to set.
Slice and enjoy!