Frosted Peanut Butter Sugar Cookies with Chocolate & Peanut Butter Frosting

Ingredients

• 1 cup butter, softened (227 g)
• 1 cup creamy peanut butter (not all natural) (255 g)
• ¼ cup vegetable oil
• 1 ¼ cup white sugar (262 g)
• ¾ cup powdered sugar (85 g)
• ½ teaspoon baking soda
• ½ teaspoon cream of tartar
• ½ teaspoon salt
• 2 tablespoons sour cream
• 2 large eggs
• 2 teaspoons vanilla extract
• 5 cups flour (708 g) *see note
• 1/3-1/2 cup sugar for dipping cup into to flatten cookie
• 1/3 cup butter (76g)
• 1/4 cup peanut butter (64 g)
• 1 tablespoon sour cream
• 1 teaspoon vanilla extract
• 2 1/4 cup powdered sugar (255 g)
• 1/3 cup cocoa powder, sifted (Dutch process, if you want it to be a darker chocolate color and taste) (28 g)
• 4-5 tablespoons heavy cream