Once hot, add the butter. Once butter has melted, add the shallots and select cancel. Sauté until the sizzling stops.
In a medium bowl, combine the corn, milk, sour cream, cornmeal, sugar, eggs, salt, and pepper. Add the butter and shallots and stir until combined.
Add the water to the insta-cooker and place the steam rack inside. Butter a 6-7 inch soufflé or baking dish, pour the mixture into it, and cover with foil. Carefully lower the pan onto the rack and secure lid.
Select manual and cook on low pressure for 30 minutes.
Once cooking is complete, use quick release. Very carefully remove the pan, let cool for a few minutes before serving.