Begin by gathering all ingredients and preheating the oven to 350°F (175°C). Place the decorating sugar into a small bowl, using separate bowls if you wish to use multiple colors.
In a stand mixer, beat the softened butter and shortening together on medium speed until the mixture is smooth and creamy, about 2 to 3 minutes. Gradually blend in the granulated sugar, then add the eggs one at a time, ensuring to scrape down the sides of the bowl as needed. Mix in the vanilla extract until fully incorporated.
In a separate medium bowl, whisk together the flour, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, mixing until a cohesive dough forms.
Shape the dough into balls, each roughly the size of a walnut. Roll each ball in the decorating sugar to coat evenly, then arrange them on ungreased baking sheets, leaving 2 inches between each ball.
Bake in the preheated oven for 10 to 12 minutes, rotating the baking sheets between racks halfway through the baking time. When the bottoms are a light golden brown, remove the cookies from the oven and transfer them to wire racks to cool completely.
