Preheat the oven to 375 degrees F. Grease the inside of an 8 to 10-cup baking dish.
Melt the butter in a very large saute pan and saute the corn and onion over medium-high heat for 4 minutes. Cool slightly.
Whisk together the eggs, milk, and half-and-half in a large bowl. Slowly whisk in the cornmeal and then the ricotta. Add the basil, sugar, salt, and pepper. Add the cooked corn mixture and grated cheddar, and then pour into the baking dish. Sprinkle the top with more grated cheddar.
Place the dish in a larger pan and fill the pan 1/2 way up the sides of the dish with hot tap water. Bake the pudding for 40 to 45 minutes until the top begins to brown and a knife inserted in the center comes out clean. Serve warm.