Similar to how I make Chicken Bone Broth Stock Cubes, I also make shellfish stock for use in soups. There’s a huge amount of flavor in the shells, don’t throw them away!

I started with lobster and shrimp, frozen, and defrosted.

Removed all the delicious meat (which I think cooked sous vide style).

And what do you do with the leftover shells? There’s a huge amount of flavor in those shells! I will make stock right away, or sometime just freeze the shells until I have enough to make stock.

I keep cuttings and ends of celery, carrots, onions and leeks in my freezer until I’m ready to make the stock. There is a huge amount of flavor in the trimmings, and it feels so wasteful to throw away the food. Also, because you’re going to cook it in the pressure cooker, it’s absolutely sterile after cooking. Just throw in a handful of each.
My current Instant Pot is the Instant Pot Max. I love the max pressure and the fact that it has automated release valves.
Add 2- 3 cups of water, and cook on max pressure for 4 hours (high for 4 1/2 hours). I will usually use natural vent for this unless I’m in a hurry. Strain the stock. If you’re not using immediately, freezing in ice cube trays similar to these is very convenient.

And use to make such things as Lobster Bisque.

I will often add several bone broth cubes in addition to the stock made from the shellfish shells. I do this because shellfish shells do not have the same amount of collagen, and the melted collagen in the bone broth contributes to a very velvety texture in soups. The combination of the two is amazing!
[…] Be sure to save the shells! They make an amazing shellfish stock, perfect for lobster bisque. […]