If you don't have an Instant Pot, you should be able to place the cake-filled ramekins on a baking sheet and bake at 400 degrees for 12 to 15 minutes. Note that I have not personally tested this, so I can't say for sure, but I do think this will work! If you do decide to bake them, I would suggest checking them right at 12 minutes and, if the center jiggles while being gently shaken, remove them from the oven.