Preheat the oven to 350℉. Line a 12-count muffin tin with cupcake liners.

In a large bowl, mix together the white sugar, brown sugar, oil, eggs, and pumpkin puree until smooth. In another bowl, whisk together the flour, baking powder, baking soda, salt, and spices.

Add the flour mixture to the combined wet ingredients and stir just until no streaks of flour remain. Fill each cupcake liner to the top with batter, distributing all the batter evenly between the 12 cupcakes.

Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out clean. Let cool in the pan for 10 minutes before transferring to a wire rack to finish cooling completely before frosting.

Melt the butter, brown sugar, and 2 tablespoons of whipping cream in a small saucepan over medium heat. Bring the mixture to a boil for 3 minutes while stirring constantly. Pour the cooked mixture into a heat-safe bowl and let cool uncovered at room temperature for 1 hour.

Add the icing sugar and 4 tablespoons to the cooled mixture and use an electric handheld mixer starting on low speed to whip until fluffy. The frosting might be runny, so cover and refrigerate for 15-20 minutes to harden slightly. Beat the cooled frosting on high speed until fluffy.

Fill a piping bag with the frosting and pipe onto the cooled cupcakes using your desired piping tip/design. (I used a Wilton 1M tip for the picture design.) Enjoy