Mix the beans, corn, rice, sour cream, salsa, tomato paste and seasoning in a large dutch oven over medium heat.
Pinch off small pieces of cream cheese and drop into the pot. Continue to heat until melted.
If finishing on the stove, spread the shredded cheese on top of the mix, turn the heat to very low and cover the pot with a lid. It's ready when the cheese is melted.
If finishing in the oven, transfer the mix to an ovenproof baking dish.
Top with the shredded cheese and bake in a preheated 350°F/180°C oven for 20 minutes or until the casserole is golden brown and bubbly.