Make the cupcakes: Position racks in the upper and lower thirds of the oven; preheat to 350 degrees F. Line two 12-cup muffin pans with liners. Whisk the flour, cinnamon, baking powder, baking soda, salt, nutmeg and cloves in a medium bowl. Combine the brown sugar, eggs, melted butter, pumpkin puree and vanilla in a large bowl and whisk until smooth. Add the flour mixture and whisk until just combined.
Divide the batter among the prepared muffin cups, filling each about two-thirds of the way. Bake, switching the pans halfway through, until the tops of the cupcakes spring back when gently pressed, 25 to 30 minutes. Let cool 5 minutes in the pan, then transfer to a rack to cool completely.
Meanwhile, make the frosting: Combine the granulated sugar, cream of tartar, egg whites and salt in a large heatproof bowl set over a saucepan of simmering water (do not let the bowl touch the water). Whisk until the mixture is warm and the sugar dissolves, 2 to 3 minutes. Remove the bowl from the pan, add the vanilla and beat with a mixer on medium-high speed until the frosting is cool and stiff glossy peaks form, 4 to 6 minutes.
Transfer the frosting to a piping bag fitted with a large round tip; pipe onto the cupcakes. Brown the frosting with a kitchen torch.