Ingredients

• 2 ½ cups all-purpose flour
• 2 teaspoons cream of tartar
• 1 teaspoon baking soda
• 1 pinch salt
• 2 cups brown sugar
• 1 cup peanut butter
• ½ cup shortening
• 2 eggs
• 1 ½ cups milk
• 1 teaspoon vanilla extract

Directions

1. Preheat the oven to 350 degrees F (175 degrees C). Line 24 muffin cups with paper liners.
2. Combine flour, cream of tartar, baking soda, and salt in a bowl.
3. In a large bowl, beat brown sugar, peanut butter, and shortening until light and fluffy. Beat in eggs, one at a time, then stir in vanilla. Stir in dry ingredients alternately with milk. Spoon into the prepared muffin cups.
4. Bake in the preheated oven until the tops spring back when lightly pressed, 15 to 20 minutes. Cool in the pan for at least 10 minutes before removing to a wire rack to cool completely.