1-First, start with preparing the sweet potatoes. Prick them with a fork, wrap in foil, and roast at 400ºF until tender, which takes 45 to 60 minutes, or peel, cut into cubes, and simmer on low until soft. Once cooled, scoop out the flesh and mash it with a fork for a smooth texture that adds natural sweetness to your batter.

2-Next, preheat your oven to 350ºF and line a 12-cup muffin tin with paper liners to make removal simple. In a medium bowl, whisk together the mashed sweet potato, brown sugar, vegetable oil, eggs, and vanilla extract until fully combined, creating a moist base for your cupcakes.

3-Mixing and Baking the Batter: In a separate large bowl, whisk the flour, cinnamon, ginger, nutmeg, baking powder, and salt. Gently add the sweet potato mixture and stir with a spatula just until combined overmixing can make them tough. Divide the batter evenly among the muffin cups, filling them about half full, and if there’s extra, add small spoonfuls for even baking.

4-Bake for 18 to 22 minutes, rotating the pan halfway through until the internal temperature hits 190ºF, then cool on a wire rack. This step ensures your cupcakes are perfectly done without drying out. For the frosting, bring 1 inch of water to a strong simmer in a saucepan, combine egg whites, sugar, and cream of tartar in a heat-proof bowl over the pan (without touching the water), and beat on low until stiff peaks form, about 7 minutes. Remove from heat, beat in vanilla, then pipe or spread onto cupcakes and toast with a torch or under the broiler for 1 to 1 1/2 minutes, watching closely.