If not already butterflied, prepare the shrimp by removing shell and legs, but keep tail. Slice almost all the way through starting along the back, remove vein (intestinal tract). Open the two halves up, slide a wooden skewer through the back sides to keep them opened. Thread 4 shrimp onto each skewer.
In a large skillet heat the oil, then sauté the red pepper, celery, onions and garlic until tender. Remove from heat and allow to cool.
Whisk together the pepper, egg, mustard and cheese, then stir into the sautéed veggie mixture until combined. Gently fold in the panko and crab.
Place the skewered shrimp on a parchment lined baking sheet and top with a generous helping of the mixture. Bake at 400°F for 10-15 minutes, until shrimp is pink and stuffing is hot. If desired you can always sprinkle on some grated cheese at this point and broil it until melted.
For the sauce, if desired you can peel the tomatoes, otherwise once you have squeezed out all the excess seeds and moisture, chop them up and put them in a food processor along with the garlic. Purée until smooth.
Heat the oil in a skillet, add the purée mixture and reduce by half over medium heat. Add the cold butter, and stir continuously until dissolved and sauce is creamy and glossy. Season to taste with salt and pepper.
To serve, spoon some sauce on a plate and place a prawn skewer on top.
Notes
*For low carb, replace the breadcrumbs with almond flour