Peanut Butter Sandwich Cookies

These were Sam's favorite. They are really good! I got this recipe from ourbestbites.com. They have so many good recipes.
1 c. butter flavored Crisco (I didn't have this so I used 1/4 c. butter and 3/4 c. regular shortening and I thought they turned out fine)
1 c. creamy peanut butter
1 c. sugar
1 c. brown sugar
1 tsp. vanilla
3 eggs
3 c. flour
2 tsp. baking soda
1/2 tsp. salt

Filling:
1 c. creamy peanut butter
1/2 c. butter
4 c. powdered sugar
2 tsp. vanilla
5-6 Tbsp. milk

Cream shortening, peanut butter and sugars together until light and fluffy. Add vanilla and eggs one at a time. Add dry ingredients and mix to combine. The dough will be soft. Roll the dough into small balls and roll in sugar. Squish the dough in a criss cross pattern with a fork. Place on baking sheet and bake for 6-7 minutes. You want them to be really soft so don't over bake them. Let cool and then put filling in the middle. For the filling: Cream peanut butter and butter until smooth. Add powdered sugar and vanilla. Add the milk a little at a time. You want the filling to be on the thick side.