Preheat your oven to 350°F (175°C). Line a 9x13 inch baking dish with parchment paper, leaving some overhang for easy removal.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until the mixture is light and fluffy, about 2-3 minutes. The mixture should look pale and smooth.
Add the eggs one at a time, mixing well after each addition, until fully incorporated. Then, stir in the vanilla extract to enhance the dough's aroma.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt to evenly distribute the leavening agents.
Gradually add the dry ingredients to the wet mixture, mixing on low speed or folding gently until just combined. The dough will be thick and slightly sticky.
Gently fold in the mini Easter eggs until evenly distributed throughout the dough. The colorful candies will be embedded with bits of dough around them.
Spread the cookie dough evenly into the prepared baking dish, smoothing the top with a silicone spatula to create a flat surface.
Bake in the preheated oven for about 25 minutes, or until the edges are golden brown and the centers are just set but stillsoft.
Remove from oven and allow the bars to cool completely in the dish, about 30 minutes. Cooling helps them set up for cleaner slicing.
Once cooled, lift the bars out of the dish using the parchment overhang and slice into squares or rectangles, revealing layers of chewy cookie with pops of colorful mini eggs.
Serve these cheerful cookie bars at room temperature, enjoying their chewy, layered texture and bright bursts of candy in each bite.
