Preheat your oven to 425°F. Line a large baking sheet with parchment paper.
Make the filling: In a large bowl, combine the shrimp, garlic, sour cream, panko, parsley, lemon juice, turmeric, red pepper flakes, salt, and pepper. Use your hands to mix well.
Prepare the jumbo shrimp for filling: Butterfly them by running a sharp knife along their curved backs (where the vein runs). Do not cut all the way through -- just far enough so that you can spread the bottom of the shrimp out into a wide circle. You want the tail end to stick up and arc over. The cut side should be split and facing down on your cutting board, almost creating a little lap for the filling.
Place these butterflied shrimp on your prepared baking sheet. Mound tablespoons of filling onto the laps of each of the jumbo shrimp, pressing gently so that the mixture stays in one clump when you take your hand away. Repeat with remaining shrimp and filling.
Spray all prepared shrimp with cooking spray and bake until the shrimp are bright pink and the filling is cooked through, about 15 minutes.
Serve the shrimp with lemon wedges and an additional sprinkling of fresh parsley.