Toss in the jalapeño, red bell pepper and corn and saute until tender, about 5 minutes. Season to taste with salt and pepper.
Meanwhile, whisk the cornmeal, flour, baking powder, baking soda and 1 1/2 teaspoons salt together in a large bowl. Stir in the buttermilk, eggs and melted butter, then the green onions, until combined.
Pour the batter into the hot skillet and bake until golden brown, about 25 minutes. Slice into wedges and serve with tomato butter.
Pan-Roasted Tomato Butter:
Heat a 10-inch cast-iron skillet over medium-high heat.
Set the tomato in the hot pan cut-side down. Cook until the tomato softens and is caramelized, 6 to 8 minutes.
Let the tomato cool slightly, then add to a food processor along with the butter and salt. Pulse until combined. Remove the butter with a rubber spatula to a small bowl.