In a large mixing bowl or a stand mixer fitted with the paddle attachment, beat the softened butter and granulated sugar together until the mixture is light and fluffy. This usually takes about 3 minutes on medium high speed.

Mix in the egg and vanilla extract. Be sure to scrape down the sides of the bowl to ensure everything is fully incorporated.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture on low speed until a soft dough forms. Do not overmix as this can result in tough cookies.

Turn the dough out onto a lightly floured surface and divide it into two equal portions. Leave one portion plain vanilla.

Place the second portion back into the mixer and add a few drops of pink food coloring. Mix until the color is uniform. If you want a deep red, you can use more gel, but a soft pink is classic for Valentine's Day.

Wrap each dough ball in plastic wrap and refrigerate for at least 30 minutes. Chilling makes the dough much easier to roll and prevents the colors from bleeding too much.

On a piece of parchment paper, roll the plain vanilla dough into a rectangle about 1/4 inch thick. Repeat the process with the pink dough on a separate piece of parchment paper, making sure both rectangles are roughly the same size.

Carefully flip the pink dough rectangle onto the vanilla dough rectangle. Using the parchment paper to assist you, roll the dough tightly from the long side into a log shape similar to a jelly roll.

Wrap the log in plastic wrap and chill for at least 2 hours or even overnight. This step is crucial for getting clean slices.

Preheat your oven to 350 degrees F. Use a sharp knife to cut the log into 1/4 inch thick slices. Place them on a baking sheet lined with parchment paper.

Bake for 10 to 12 minutes or until the edges are just set. You do not want them to brown. Let them cool on the baking sheet for 5 minutes before transferring to a wire rack.