Preheat oven to 400 ° Grease a 2 ½-quart casserole dish. Set aside.
Add the egg whites to a large bowl or the bowl of an electric stand mixer. Use an electric mixer with the whisk attachment to beat the egg whites into stiff peaks. Remove egg whites to a separate bowl for later use.
Add the drained sweet potatoes to the same large bowl or the bowl of an electric stand mixer. Use a paddle attachment to beat the sweet potatoes until smooth. Add the egg yolks, milk, melted butter, cinnamon, paprika and ground black pepper. Mix until smooth.
Mix in the biscuit & baking mix until there are no large clumps. Gently fold in the egg whites.
Pour batter into the prepared pan and sprinkle with brown sugar.
Bake for 55-60 minutes or until a toothpick inserted into the center comes out clean.
To serve, use a large spoon to scoop out pieces of the bread.