In a large mixing bowl, whisk together the all-purpose flour, baking powder, and salt until well combined. Set aside.
In another bowl, cream the softened butter and granulated sugar using an electric mixer or hand whisk until light and fluffy.
Beat in the egg and vanilla extract until fully incorporated.
Gradually add the dry ingredient mixture to the wet ingredients, mixing until a dough forms. Divide the dough into smaller portions if using different food colors.
Add a small amount of food-safe gel coloring to each dough portion and knead until the color is evenly distributed.
Wrap each colored dough in plastic wrap and refrigerate for at least 15-20 minutes.
Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone baking mat.
Roll out the refrigerated dough on a lightly floured surface to about 1/4-inch thickness.
Use the Christmas truck cookie cutter to cut out truck shapes from the colored dough.
Carefully transfer the truck-shaped cookies to the prepared baking sheet, leaving some space between each cookie.
With a small food-safe paintbrush, add finer details to the truck cookies using additional gel coloring.
Bake the cookies for approximately 8-10 minutes or until the edges turn golden brown.
Remove the baking sheet from the oven and let the cookies cool on it for a few minutes before transferring them to a wire cooling rack to cool completely.