1. Preheat the oven to 350 degrees F. Butter a 2-quart oval baking dish.
2. For the creamed corn: Melt the butter in a large skillet over medium heat. Add the onions, thyme, 1/2 teaspoon salt and a few grinds of pepper, and cook, stirring frequently, until the onions are soft and translucent, about 10 minutes. Add the corn and cream, and bring to a simmer, stirring occasionally, until the mixture reduces in volume and bubbles rapidly, about 15 minutes. Transfer 2 cups of the corn mixture to a food processor, puree until smooth, then stir it back into the skillet. Fold in the ham and kale. Transfer the creamed corn to the prepared baking dish; set aside. Clean the food processor bowl.
3. For the cornbread topping: Pulse the cornmeal, flour, baking powder, sugar and 1/2 teaspoon each salt and pepper in a food processor to combine. Add the butter, and pulse until the mixture resembles coarse breadcrumbs. Add the cream and 1/2 cup of the Cheddar, and pulse until the batter just comes together.
4. To assemble: Sprinkle the cornmeal batter over the creamed corn. (Don’t worry if the corn isn’t completely covered; the batter will puff and spread as it bakes.) Sprinkle with the remaining 1/2 cup Cheddar. Place the casserole on a baking sheet, and bake until the corn is bubbling and the crust is puffed and golden brown, about 35 minutes. Let cool for 15 minutes. Serve with hot sauce.