In a large bowl, beat the butter with a mixer until fluffy. At least 3 to 4 minutes. Carefully add the powdered sugar, vanilla extract, and pistachio pudding mix until combined.
1 cup butter, softened, ½ cup powdered sugar, 1 3.4 ounce package instant pistachio pudding, 1½ teaspoons pure vanilla extract
Carefully add in the flour and mix just until combined.
1⅔ cups flour
Gently mix in the chopped red cherries by hand to keep the color from bleeding. Wrap the cookie dough in plastic wrap and put it in the refrigerator for at least an hour.
½ cup red candied cherries, chopped
Preheat the oven to 350℉ and line baking sheets with silicone baking mats or parchment paper.
Using a #40 scoop, scoop cookie dough and place on the prepared baking sheet. Using a clean flat object, such as a glass or measuring cup (or your clean hand), gently press the cookie dough ball to flatten it slightly. Not too thin.
Bake cookies for 9-11 minutes or until the center is set and the edges begin to brown. Remove the cookies from the oven and allow them to cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.