Preheat Oven to 375 Degrees Fahrenheit

In a small bowl mix the flour, baking soda and salt. Set aside

Using the bowl of a mixer, cream the butter and sugars together for 3-4 minutes until creamy. Scrape the sides of the bowl down with a spatula

Add the egg, vanilla and peanut butter. Keep mixing on medium speed

Slowly add the flour mixture and mix until the cookie dough is combined

Line a cookie sheet with parchment paper or silicone mat

Using your hands, shape little balls and place them on the cookie sheet. Keep them separated because they tend to spread

Shape the cookies with a fork or a cookie stamp

Bake 8-10 minutes or until browned on top

Remove from oven and let them cool on the cookie sheet

Place the peanut butter, milk and butter on a mixer bowl. Mix on medium speed until combined

Add a tad of frosting into the middle of every other cookie. Sandwich with another one

Enjoy!