It seems to be after a certain number of deaths that this spawns. At one point you'll come to your first house but the first few times you won't be able to go inside.
At a point where you've entered the mountain in the desert, you'll be able to do this trophy upon your first death as the enemies inside here hit super hard.
When the house reappears you should be able to see a blue marker on the quest path, which is the house keys.
Pick them up and explore the house, once at the upstairs window, you'll have your trophy.