Preheat oven to 350°F (175°C) and lightly spray a baking sheet with non-stick cooking spray.
In a large bowl, beat 1 cup softened butter and 1 cup sugar together for about 2 minutes, until creamy.
Stir in 1 egg, 1 tablespoon red food coloring, and 1 teaspoon vanilla until completely blended.
In a separate bowl, whisk together 2 ½ cups all-purpose flour, 3 tablespoons unsweetened cocoa powder, and ¼ teaspoon salt. Add the dry mixture to the wet mixture and stir until a uniform dough forms.
Roll the dough into 1-inch balls and place them about 2 inches apart on the prepared baking sheet.
Press a thumb into the center of each dough ball to create an indentation, being careful not to press all the way through to the baking sheet.
Bake the cookies for 10–12 minutes. Remove from oven and let the cookies cool on the baking sheet for about 5 minutes, then transfer them to a wire cooling rack to cool completely.
To make the filling, in a medium bowl whisk 2 tablespoons softened butter and 2 ounces softened cream cheese together for 1–2 minutes until light and fluffy. Add ½ teaspoon vanilla and stir to combine.
Gradually add 2 cups powdered sugar to the cream cheese mixture, mixing until fully incorporated and the filling is smooth enough to pipe or spoon.
Pipe or spoon the cream cheese filling into the thumbprint indentation of each cooled cookie.
If desired, add sprinkles on top of the filling before it sets.