In a large bowl mix together mayonnaise, both mustards, a generous dash of hot sauce, horseradish, and the egg.
Gently stir in the saltines and crabmeat.
You may form the crabcakes immediately, however allowing the mixture to sit in the refrigerator for 1 hour will make the shaping easier.
Divide the mixture into 4-6 large crabcakes, and place on a lightly oiled or nonstick baking sheet. (Or make to your desired size - I use a 1/4 cup measure - and adjust your cooking time appropriately ).
Bake for 15-20 minutes , or until a light golden brown.
Baltimore Crab Cakes: Add a dash of Worcestershire sauce and Old Bay Seasoning to taste.