Preheat oven to 375 degrees. Butter a small casserole dish. Reserve.
Peel and devein shrimp, leaving tails attached. Using a small pairing knife slice almost through the back of each shrimp. This allows you to flatten them to make room for the stuffing. Reserve.
Melt 2 Tbl. butter in a medium skillet. Saute shallot until tender, then add in garlic, scallion, and parsley and cook for another 1-2 minutes. Toss in spinach leaves. Cover and remove from heat, allowing to spinach to wilt. Mix in crumbled crackers and macadamia nuts. Allow stuffing to cool before use.
Using hands, form 1/5th mixture into a ball and press onto the back of the shrimp as shown in photo. Place into buttered casserole dish. Continue with all five shrimp. Shrimp can now be chilled until ready to bake or up to 8 hours. Just before baking melt 1 Tbl. butter and drizzle over each stuffing mound.
Bake for 20 minutes.
Notes
This recipe could easily be doubled or quadrupled. The stuffing can be changed up by adding lovely lump crabmeat.