3/4 cup butter
1 1/2 cup white sugar
1/4 cup light brown sugar
1 1/2 Tbsp molasses
1 tsp kosher salt
2 cups all purpose flour
1 tsp baking powder
1 tsp ground cinnamon
2 cups quick-cooking rolled oats
2 tsp baking soda
3 Tbsp boiling water
1 Tbsp plus 1 tsp unflavored gelatin (about 1 1/2 packets)
1/3 cup plus 1/4 cup water (divided)
3/4 cup sugar
1/4 cup light corn syrup
2 tsp vanilla
1 cup powdered sugar
8 oz vegetable shortening
Preheat oven to 350°
Line your baking sheets with parchment paper...this is an important step.
Cream the butter, sugars, and molasses together with your mixer.
Add eggs and mix on medium until combined.
In a separate bowl, whisk together the salt, flour, and baking powder. Add to the creamed mixture. Add the cinnamon and oats. Mix well.
In a small dish, add the baking soda to the boiling water, and then stir the mixture into the rest of the batter. Mix well.
Drop by rounded tablespoon onto the baking sheets about 2 inches apart and bake until the cookies are golden around the edges, 10 to 12 minutes.
The cookies will look slightly wet in the middle..just go by the color of the edge.
Let the cookies cool completely on the parchment lined baking sheet and carefully move to a wire rack.
The cookies will be soft and fragile, so be extra careful when moving them!
For the filling:
In a small bowl, sprinkle the gelatin over 1/3 cup cold water.
Stir it together and let it stand about 5 minutes.
In a 2-quart saucepan over medium-high heat, stir together the granulated sugar, corn syrup, and 1/4 cup hot water until well blended. Continuing to stir, raise the heat to high and bring to a full boil. Continue boiling for 30 seconds. Immediately remove from the heat. Stir in the gelatin mixture until it dissolves completely.
Transfer the mixture to a large bowl. Add the vanilla.
With your mixer on medium speed, beat for 20 seconds. Gradually raise the speed to high and beat until the mixture is stiffened, white, very fluffy, and cooled to barely warm, about 5 minutes.
Reduce the mixer speed to low and gradually add your powdered sugar.
Add your shortening and beat until completely smooth.
The filling will set up as it sits, so wait until it is thick enough to spread or pipe before filling the cookies, but don't let it sit too long, though because it will become a giant marshmallow!!
Let the cookies set up for about 20-30 minutes and they will be PERFECT!