1. Preheat oven to 350. Butter a deep 1-1/2 quart baking dish, and add cooked macaroni.
2. In a blender or food processor combine egg, milk, and garlic, and process 3 seconds. Add onion, cheeses, peppers, salt, and paprika, and blend 10 seconds. Turn into the baking dish, folding into macaroni.
3. Melt butter in a small saucepan. Coat crackers with butter and spread over top of casserole. Bake about 30 to 35 minutes, or until thick yet creamy. Remove from oven, let stand about 5 minutes and serve.
Lynne Rossetto Kasper has won numerous awards as host of The Splendid Table, including two James Beard Foundation Awards (1998, 2008) for Best National Radio Show on Food, five Clarion Awards (2007, 2008, 2009, 2010, 2014) from Women in Communication, and a Gracie Allen Award in 2000 for Best Syndicated Talk Show.