Preheat oven to 350 degrees. Prepare mini cupcake tins by lightly spraying, greasing and flouring, or lining with paper liners. In a large bowl, beat butter, sugar and brown sugar until light and fluffy. Mix in pumpkin and eggs until well blended. Add salt, cinnamon, nutmeg, ginger and cloves. With a mixer on low, add flour, baking powder and baking soda. Fill mini cupcake 2/3 full (about 1 tablespoon of batter.) Place in oven and bake for 10-15 minutes, until tops are lightly golden and cupcakes lightly spring back when touched. Cool completely and prepare brown sugar butter cream.

Brown Sugar Butter Cream:

In a heavy pot, dissolve brown sugar and water. Place over medium high to high heat, and heat to 240 degrees using a candy thermometer. While sugar is cooking, place egg whites and cream of tarter in a stand mixer and beat to soft peaks. Once sugar has reached the correct temperature, slowly stream the sugar mixture into the egg whites, while the mixer is on medium to medium high. Once finished, scrape down bowl and continue beating for 10-12 minutes, until at room temperature.

Turn mixer down to low or medium and add butter, one piece at a time, waiting until the previous piece is well incorporated. Add vanilla and cinnamon, then pipe onto cooled cupcakes.