Preheat oven to 350°.
Press spinach into the bottom of a 13 x 9-inch baking dish coated with cooking spray. Form 6 (3-inch) indentations in spinach layer using the back of a spoon or bottom of a large custard cup. Break an egg into each indentation.
Combine flour, salt, and red pepper in a medium saucepan. Gradually add the milk, stirring with a whisk until blended. Place milk mixture over medium heat, and cook until thick (about 8 minutes), stirring constantly. Remove from heat; add cheese, stirring until cheese melts. Pour cheese sauce over eggs and spinach; sprinkle with paprika. Bake at 350° for 25 minutes or until egg yolks are almost set. Cut spinach-egg mixture into 6 portions; serve each portion over 2 English muffin halves, and sprinkle with black pepper.