Roast the red pepper in a 350° F/175° C toaster oven or in a dry skillet, turning until all sides are charred, about 5 to 8 minutes. Allow the roasted pepper to cool in a paper bag, then slip off the charred skin. Discard the seeds and stem, and dice the pepper.
In the medium bowl, stir together the mayonnaise, sour cream, diced pepper, onion, ground red pepper, crab meat, and shredded cheddar cheese. Spread evenly in the prepared baking dish.
Bake in the preheated oven until bubbly and lightly browned on top, about 20 to 25 minutes. Serve with sliced baguette, crackers, pita wedges, or chips.