If you don't have silicone molds made specifically for the Instant Pot, then by all means you can use a ramekin. Depending on the size of your Instant Pot, you could potentially fit about 4 in there at once. Alternatively, you could also use a mason jar as long as they are OVEN SAFE! Glass containers will heat up differently than silicone, so you may find that you need to adjust your cook time.