Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

In a large bowl, cream together the room-temperature unsalted butter and granulated sugar until light and fluffy.

Add the room-temperature eggs and vanilla extract, mixing until just combined.

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

Press the dough into the prepared pan evenly and smooth the surface.

Bake for 18-22 minutes or until the edges are light golden and the center is slightly underbaked.

Allow to cool completely in the pan for about 45-60 minutes.

Prepare the frosting by mixing powdered sugar, milk, and vanilla extract until smooth. Optionally, tint with gel food coloring.

Frost the cooled bars and add decorations before the frosting sets.

Cut into squares and serve.