Put the onion, bell pepper, jalapeño and butter in a microwave safe dish and cook until butter is melted and veggies are getting soft. (Approx. 3-4 minutes)
Add all the ingredients, including the butter and veggies, into a slow cooker.
Stir completely using a wooden or plastic spoon.
Set on low for approx. 5 hours.
Recipe by Sports Mom Survival Guide at https://www.sportsmomsurvivalguide.com/slow-cooker-corn-casserole/