sweet corn spoonbread

INGREDIENTS

• 1 cup cornmeal
• 2 3/4 cups whole milk
• 4 tablespoons unsalted butter, plus additional for greasing dish
• 2 cups corn kernels (from 3 to 4 ears of corn, or frozen, if defrosted and well drained)
• 1 teaspoon sugar
• 1 teaspoon salt
• 1/8 teaspoon cayenne
• 3 large eggs, separated
• 1/4 teaspoon cream of tartar