I recently adapted a recipe from Cook's Illustrated for this, omitting the flour and the breadcrumb topping. My husband actually ATE this. Their recipe calls for parmesan cheese, and the tiniest pinch of cayenne. Also, it calls for shallots (at least, I think it does... my memory is not working well) instead of onions: La, de, da!
Anyway... I was thinking of using crumbled bacon as a replacement for the breadcrumb topping, or some combination of pork rinds (which my husband considers disgusting) and a slice of low carb bread or ry-vita cracker.