Make the cilantro lime cream by mixing sour cream, lime juice, salt and pepper, and chopped cilantro. Refrigerate until needed.
Peel and devein shrimp. If frozen, thaw them under cool running water first. Pat them dry with paper towel.
Pre-heat oven to 350F (to warm tortillas), wrap tortillas in foil and place in oven.
Prepare lettuce and onions. Set aside.
Make the batter by adding garlic powder, salt, pepper, flour, and beer to a bowl. Mix until smooth.
Add about 1/4 inch of peanut oil to a skillet. Heat on medium high.
Once oil is ready, dip shrimp in batter and then carefully place shrimp in the hot oil (I usually end up doing three batches). Cook for a few minutes per side until golden and cooked through.
Serve tacos with the lettuce, onions, and cilantro lime cream drizzled over.