Preheat your oven to 350°F (175°C) and line an 8×8-inch baking pan with parchment paper.

Cream the unsalted butter and granulated sugar together in a mixing bowl until light and fluffy, about 2-3 minutes.

Add the eggs and vanilla extract to the butter mixture and mix until just combined.

In a separate bowl, whisk together the flour, baking soda, and salt, then gradually add to the wet ingredients until a thick dough forms.

Press the dough evenly into the prepared baking pan.

Bake for 18-22 minutes until edges are set; the center should be soft.

Allow the bars to cool completely in the pan on a wire rack for 45-60 minutes.

Prepare the frosting by mixing powdered sugar, milk, and vanilla extract until smooth; optionally add gel food coloring.

Spread the frosting over the cooled bars and add decorations if desired.

Cut into 9 or 16 squares and serve.