In a 12 oz. microwave safe mug, combine milk, pumpkin puree, vanilla, and sugar.
Add cinnamon, ginger, clove, nutmeg, and salt. Can substitute with ¾ teaspoon pumpkin pie spice. Mix well.
Add flour and baking powder, and stir until combined. Don't overmix, it will result in a chewy, less fluffy mug cake. Place caramels one on top of the other in the center of the batter and press down slightly until only the top of the caramel is showing. Don't push all the way under the batter.
Microwave on high power for 2 minutes. Sometimes the mug cake rises a little above the edge of the mug, it shrinks back down as it cools. It's never overflowed for me.