Preheat oven to 350°. Spray bottom of a shallow 2-quart baking dish with cooking spray. Set aside.
In a large saucepan, combine cornmeal, flour, sugar, salt, and pepper; whisk in milk and hot sauce. Bring to a boil over medium heat, stirring constantly. Reduce heat to medium-low; cook until very thick, stirring frequently, about 5 minutes. Remove from heat. Add 1 cup cheese and pimientos, stirring until cheese melts.
In a medium bowl, place egg yolks. Whisk half of hot cornmeal mixture into egg yolks; whisk egg yolk mixture into remaining cornmeal mixture in saucepan.
In another medium bowl, beat egg whites and baking powder with a mixer at high speed until soft peaks form; gently fold into cornmeal mixture. Spoon into prepared dish; top with remaining ¼ cup cheese.
Bake until puffed and golden, 30 to 35 minutes. Sprinkle with chives.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/pimiento-cheese-spoon-bread/