Preheat your oven to 350°F (175°C). Lightly grease a 9x13 inch baking pan or line it with parchment paper.

In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, beat the softened butter and granulated sugar until light and fluffy.

Beat in the eggs one at a time, then stir in the vanilla extract.

Gradually mix the dry ingredients into the wet mixture until just combined.

Spread the dough evenly in the prepared baking pan and bake for 20-25 minutes or until edges are lightly golden and a toothpick inserted in the center comes out clean.

Allow the bars to cool completely in the pan.

In a mixing bowl, beat the softened butter with the powdered sugar until smooth and creamy. Add in milk and vanilla extract.

If using food coloring, divide the frosting into different bowls to create various colors.

Spread the colorful frosting atop the cooled sugar cookie bars.

Finish with mini chocolate eggs or candy-covered eggs scattered on top for decoration.

Cut the bars into squares or rectangles for easy serving.