In a small bowl, cream the softened butter and granulated sugar until pale and fluffy.
Stir in the pumpkin purée and vanilla extract until combined.
Add the flour, baking powder, salt, pumpkin pie spice, nutmeg, and cloves. Mix just until no dry flour remains — do not overmix.
Grease a 10 to 12 ounce ramekin or oven-safe mug and scrape in the batter. Fill no more than two-thirds full.
In the same bowl, rub the cold butter into the flour and brown sugar until it forms coarse, pea-sized crumbs. Scatter evenly over the batter without pressing down.
Place the ramekin in the air fryer basket. Cook at 320°F for 10 to 12 minutes, checking at 8 minutes. A toothpick inserted into the center should come out clean.
Let cool at least 5 minutes before eating.