Whisk the flour, baking powder, and salt together in a medium bowl. Set aside.

In a large bowl using a handheld or a stand mixer fitted with a paddle attachment, beat the butter and sugar together on high speed, about 3 minutes. (Here’s a helpful tutorial if you need guidance on how to cream butter and sugar.) Add the vanilla bean seeds and beat again until combined and butter is creamy, about 1-2 more minutes. Add the egg and vanilla extract and beat on high speed until combined, about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine.

Add the dry ingredients to the wet ingredients and beat on low speed until combined. Dough will be a bit soft. If the dough seems too soft and sticky for rolling, add 1 more Tablespoon of flour.

Divide the dough into 2 equal portions. Place each portion on a piece of lightly floured parchment paper or a lightly floured silicone baking mat. With a lightly floured rolling pin, roll the dough out to about 1/4-inch thickness. Use more flour if the dough seems too sticky. The rolled-out dough can be any shape, as long as it is evenly 1/4-inch thick.

Lightly dust one of the rolled-out doughs with flour. Place a piece of parchment on top. (This prevents sticking.) Place the 2nd rolled-out dough on top. Cover with plastic wrap or aluminum foil and then refrigerate for at least 1-2 hours and up to 2 days.

Once chilled, preheat oven to 350°F (177°C). Line 2-3 large baking sheets with parchment paper or silicone baking mats. Carefully remove the top dough piece from the refrigerator. If it’s sticking to the bottom, run your hand under it to help remove it. Using a cookie cutter, cut the dough into shapes. Re-roll the remaining dough and continue cutting until all is used. Repeat with 2nd piece of dough. (Note: It doesn’t seem like a lot of dough, but you get a lot of cookies from the dough scraps you re-roll.)

Arrange cookies on baking sheets 3 inches apart. Bake for 11-12 minutes or until lightly browned around the edges. If your oven has hot spots, rotate the baking sheet halfway through bake time. Allow cookies to cool on the baking sheet for 5 minutes and then transfer to a wire rack to cool completely before decorating.

With a handheld or stand mixer fitted with a paddle attachment, beat the butter and vanilla bean seeds together on medium speed until butter is creamy, about 2 minutes. Add confectioners’ sugar, heavy cream, and vanilla extract. Beat on low speed for 30 seconds and then increase to medium-high speed and beat for 2 full minutes. Taste. Add a pinch of salt if frosting is too sweet. To color the frosting, divide the frosting between 2-3 bowls (or however many colors of frosting you want). Stir in 1-2 tiny drops of gel food coloring (or more, depending on your desired color).

You can decorate the cookies with a knife, icing spatula, or use a piping bag and piping tip. Top with sprinkles, if desired. In the pictured cookies, I filled a piping bag with spoonfuls of both green and uncolored frosting and used Ateco 30 piping tip. Pipe hearts as the 3 leaves and a line as the stem.

Frosting does not harden or crust very much, though you could gently stack 1 frosted cookie on top of another, but expect some slight squishing. Store frosted cookies covered at room temperature for up to 1 day or in the refrigerator for up to 1 week. Store unfrosted cookies covered at room temperature for up to 5 days or in the refrigerator for up to 1 week.