Stir together sour cream, Tahini Sauce, garlic puree, ground cumin, and lemon juice to make Sour Cream and Tahini Sauce (if using) and refrigerate until you’re ready to serve the shrimp. The sauce can be made ahead.
Preheat the oven to 400F/200C.
Spray a large baking sheet with non-stick spray.
Thaw shrimp overnight in the refrigerator (or thaw in the bag in cold water if you forget to plan ahead.)
Drain shrimp well in a colander placed in the sink, then put a paper towel on a cutting board and spread the shrimp out in a single layer.
Cover with another paper towel and press down on the towel to blot the shrimp dry.
Whisk together the crushed garlic, Aleppo Pepper (affiliate link), olive oil and Ground Sumac (affiliate link) if using.
Put the shrimp into a plastic bowl and toss with the olive oil-spice mixture.
Spread shrimp out in a single layer on the baking sheet.
Roast shrimp until they’re pink and firm but not hard to the touch, about 6-8 minutes. Larger shrimp with take slightly more time than smaller ones; start to check after about 5 minutes.
Serve hot, with Sour Cream and Tahini Sauce if desired.
