Take your favorite brownie recipe and make it - use duck eggs for super fluffy cupcakes!
Spoon into greased muffin tins or ovensafe mugs and stick a large marshmallow in the middle of each.
Cook for 1 hour at lowish heat 300 degrees F with the blower on (if you don't have a convection oven 325 degrees - same time but check with a toothpick to see if they are done)
When they cool - eat either popped out of the pan (slide a knife around to be sure they don't stick)
or with a spoon if you made them in a mug.
If it's cold outside serve with hot frothy steamed milk, if warm with ICE CREAM!