Preparation Heat 1 1/2 tablespoons vegetable oil in heavy large skillet over medium-high heat. Add finely chopped onion and sauté until soft and beginning to brown, stirring often, about 12 minutes. Cool. Preheat oven to 350°F. Spray 8x8x2- inch metal baking pan with nonstick spray. Whisk flour, cornmeal, baking powder, and salt in small bowl. Whisk egg, 1/3 cup cheese blend, 1/2 cup sour cream, creamed corn, and remaining 2 tablespoons oil in large bowl. Add flour mixture; stir to blend. Stir in jalapeño and caramelized onions. Transfer batter to prepared pan. Sprinkle remaining 1/3 cup cheese blend over. Bake until puffed and tester inserted into center comes out clean, about 35 minutes. Cool completely. do ahead Custard squares can be made 2 hours ahead. Let stand at room temperature. Cut into 1-inch squares. Place on platter. Top each square with dollop of sour cream, then small spoonful of salsa.
Preparation Heat 1 1/2 tablespoons vegetable oil in heavy large skillet over medium-high heat. Add finely chopped onion and sauté until soft and beginning to brown, stirring often, about 12 minutes. Cool. Preheat oven to 350°F. Spray 8x8x2- inch metal baking pan with nonstick spray. Whisk flour, cornmeal, baking powder, and salt in small bowl. Whisk egg, 1/3 cup cheese blend, 1/2 cup sour cream, creamed corn, and remaining 2 tablespoons oil in large bowl. Add flour mixture; stir to blend. Stir in jalapeño and caramelized onions. Transfer batter to prepared pan. Sprinkle remaining 1/3 cup cheese blend over. Bake until puffed and tester inserted into center comes out clean, about 35 minutes. Cool completely. do ahead Custard squares can be made 2 hours ahead. Let stand at room temperature. Cut into 1-inch squares. Place on platter. Top each square with dollop of sour cream, then small spoonful of salsa.