Preheat oven to 375 degrees F.

In a mixing bowl cream together butter, shortening, peanut butter, 1/2 cup granulated sugar, and brown sugar until light and fluffy, about 2 minutes.

Add and eggs, mixing after each addition. Mix in the vanilla.

In a separate bowl whisk together flour, baking soda, and salt.

Stir dry ingredients into the wet ingredients and mix gently to combine. Don't over-mix. The dough will be very soft.

Pour remaining 1/2 cup of granulated sugar into a small bowl. Line a cookie sheet with parchment paper.

Scoop dough into balls and then roll in sugar.

Bake for 7-10 minutes, just until set. They will be pale, and look just barely set. Don't over-bake them or they will be hard once cooled.

Remove from oven and allow to cool on baking sheet for 2-3 minutes, and then transfer to cooling rack.

Press an unwrapped Reese's heart to the center of each warm cookie. Allow cookies to cool completely.

Store leftover cookies in a container at room temperature, or they freeze very well.