Preheat your oven to 350°F (175°C) and line a 9x9 inch baking pan with parchment paper for easy removal.
In a large mixing bowl, beat softened butter and sugar together until the mixture is light and fluffy, and smells sweet and buttery, about 2-3 minutes.
Add the egg to the butter mixture and beat until well combined, ensuring the mixture is smooth and slightly glossy.
In a separate bowl, whisk together the flour, baking powder, and salt to evenly distribute the leavening agents.
Gradually add the dry ingredients to the wet mixture, folding in with a spatula until just combined and the dough feels soft but manageable.
Press the dough evenly into the prepared baking pan, smoothing the top with a spatula for an even layer.
Bake in the preheated oven for about 18-20 minutes, or until the edges are golden brown and the center is just set.
Remove the pan from the oven and let the cookie base cool in the pan for 10 minutes until it slightly firmed up, making it easier to handle.
Sprinkle the mini chocolate eggs evenly over the warm cookie layer, pressing lightly to embed some into the surface.
Allow the bars to cool completely before slicing into squares, revealing the colorful mini eggs and crisp edges.
Cut into individual bars and enjoy the contrast of crunchy edges and chewy center with your colorful mini eggs shining through.
