Objective: put all the cards in the trash as fast as possible.
Pick a kingdom of your choice, satisfying the recommended rules. Solo play, the shuffles always favor you, 0 <= #Events + #Landmarks <= 2,
Colony and
Platinum are allowed if you have at least one randomizer card from Prosperity and required if all randomizers are from Prosperity; similarly for shelters.
I'm not sure that
Black Market helps you; if you use it, some people like solutions that work online—bonus points for making them happy.
Hard mode: 2+ players, your opponents do nothing, you have trash all of their cards as well.
Rules reminder: if you trigger the game-end condition and buy
Donate on the same turn, you never get to do the Donate thing. (That's a Dominion rule, not a this-particular-challenge rule.)