In a large mixing bowl, whisk flour, baking powder, and salt.

In a separate bowl or the bowl of a stand mixer, add butter and granulated sugar and mix on high speed until light and fluffy. Beat in the eggs, followed by the vanilla bean paste.

Add the dry ingredients and mix until just combined.

Divide the dough into three equal portions. Wrap two of the portions in clingfilm/plastic wrap and transfer to the refrigerator to chill.

Now, divide the third portion into six smaller balls of dough. Add a few drops of a different gel food coloring to each, creating red, orange, yellow, green, blue, and purple doughs.

Use a sharp chef’s knife to chop all of the colored doughs into small pieces. If desired, you can also use your hands to break the dough apart. You can make the pieces as large or as small as you’d like, and it’s perfectly fine if they’re all a little bit different!

On a tray lined with baking parchment, combine the rainbow dough pieces to create a mosaic pattern. Use your fingers to gently push the pieces together, making sure there are no gaps. Top with a second sheet of baking parchment, and use a rolling pin to roll the rainbow dough to 1/4-inch (6 millimeters) thickness. Transfer tray to the refrigerator to chill for at least one hour.

Once chilled, use a heart-shaped cutter to cut the rainbow dough into hearts. Stack the hearts on top of one another, then place the stack in the freezer to chill for at least 15 minutes, or until firm.* At the same time, remove the reserved white dough from the refrigerator and allow it to soften slightly.

Remove the heart stack from the refrigerator. Wedge bits of white dough into the crevasses of the heart shape, then wrap the remaining dough around the stack to form a log. Roll log in rainbow sprinkles or nonpareils.**

Wrap the log in clingfilm/plastic wrap and freeze until firm, at least one hour. Remove from freezer and slice into 1/4-inch (6 millimeter) cookies.

Transfer slices to a baking sheet lined with parchment or a silicone baking mat. Return tray to the freezer and freeze for 15 minutes (this will prevent the cookies from spreading in the oven). While cookies freeze, preheat oven to 300° F / 148° C.

Bake for 10-12 minutes, or until just lightly brown. Allow cookies to cool slightly on the baking tray, then transfer to a wire rack to cool completely.

Store cookies in an airtight container at room temperature for up to five days.