Marinate shrimp in seasoning and lemon juice and let sit an hour in fridge.
In hot pan, add butter (it may smoke some, but that’s ok). Lay shrimp in one at a time, searing on both sides, about 2 minutes each. Shrimp should be firm to touch and be curled.
Remove shrimp, from pan. If butter is not burnt, you definitely want to use it because there’s a lot of flavor in it. If it is burnt, remove and add new butter.
Now add in chorizo and onions and cook till chorizo has rendered some of its fat and the onions are translucent. Place in a small container.
To assemble: Place one shrimp on top of grit cake, and top with the chorizo-onion mixture, and top with cilantro.