Pasilla Mole Cupcakes recipe

For the cupcakes:
2 c. piloncillo (dark brown sugar may be substituted)
1/2 c. shortening
2 large eggs
1 1/2 c. buttermilk
2 1/2 c. all-purpose flour
1 tsp. baking soda
2 tsp. cream of tartar
1/2 tsp. salt
10 oz. Mexican chocolate (semi-sweet American chocolate may be substituted)
2 tbsp. pumpkin seeds
1 tsp. pasilla chile, ground
3/4 tsp. cinnamon, ground
1/2 tsp. cloves, dried, whole
1/4 tsp. black pepper, ground
1/4 tsp. ancho chile, ground
For the frosting:
4 large egg whites
3/4 c. white sugar, granulated
4 tbsp. unsalted butter, softened
1/4 c. cocoa powder
1/2 tsp. cream of tartar
1/3 c. sesame seeds