1. In a medium sauté pan over medium heat, melt 4 tablespoons of the butter and add the onion, celery, pepper and mushroom. Sauté for five minutes and remove from heat.
2. In a food processor, pulse both crackers to a fine crumb and pour into a medium bowl.
3. Add crab meat to the bowl with the crackers along with the cooked vegetables, hot pepper powder, beaten egg, mayonnaise, lemon juice and clam juice. Mix to combine.
4. Preheat oven to 375°F.
5. If shell is still on shrimp, remove but leave tail piece on.
6. To fill shrimp, take cut side and press down (tail sticking up) so the flesh flattens out. If you have to, make the cut side a little deeper so they flatten.
7. Divide the filling between the number of shrimp and ball over the flattened side and tuck the tail in over the top.
8. Place on a sheet pan or casserole dish that has been sprayed with kitchen pan spray.
9. Drizzle one tablespoon of butter over the tops.
10. Bake for 20 minutes, remove and drizzle the remaining butter over the tops. If any liquid is left in the pan, pour that over the tops of the shrimp as well.
11. Serve immediately.