Preheat oven to 400°.
Melt 1 tablespoon butter in a large nonstick skillet over medium-high heat. Add onion and garlic to pan; cook 2 minutes, stirring occasionally. Add corn, jalapeño, and 1/4 teaspoon salt; cook 2 minutes. Remove from heat; add 2 tablespoons butter, tossing to melt.
Spoon flour into a dry measuring cup; level with a knife. Combine flour, remaining 3/4 teaspoon salt, cornmeal, and next 4 ingredients (through chili powder) in a large bowl. Combine buttermilk, eggs, and egg white in a large bowl. Add onion mixture to buttermilk mixture. Add buttermilk mixture to flour mixture, stirring just until moist. Spoon batter into 15 muffin cups coated with cooking spray. Bake at 400° for 20 minutes or until lightly browned. Cool in pan 5 minutes on a wire rack; remove from pan. Cool muffins completely on wire rack.
Combine remaining 3 tablespoons butter, juice, and honey in a small bowl; stir until well blended. Serve with muffins.