Preheat your oven to 350°F (175°C).
In a large bowl, mix the peanut butter and sugar until smooth.
Add the egg and vanilla extract, then mix well.
In another bowl, combine the flour and baking soda.
Gradually add the dry ingredients to the peanut butter mixture.
Scoop tablespoon-sized portions and roll into balls.
Place the balls on a lined baking sheet and press down slightly.
Bake for 10-12 minutes until edges are golden.
Immediately press a mini peanut butter cup into each cookie.
Let cool on the baking sheet for 5 minutes before transferring to a wire rack.