1. Toss 2 teaspoons minced garlic, shrimp, 1 tablespoon oil, and 1/4 teaspoon salt in medium bowl. Let shrimp marinate at room temperature 20 minutes.

2. Heat 4 smashed garlic cloves and remaining 2 tablespoons oil in 12-inch skillet over medium-low heat, stirring occasionally, until garlic is light golden brown, 4 to 7 minutes. Remove skillet from heat and use slotted spoon to remove garlic from skillet; discard garlic. Set skillet aside.

3. Bring 4 quarts water to boil in large Dutch oven over high heat. Add 1 tablespoon salt and pasta. Cook until just al dente, then drain pasta, reserving 1/4 cup cooking water, and transfer pasta back to Dutch oven.

4. While pasta cooks, return skillet with oil to medium heat; add shrimp with marinade to skillet in single layer. Cook shrimp, undisturbed, until oil starts to bubble gently, 1 to 2 minutes. Stir shrimp and continue to cook until almost cooked through, about 1 minute longer. Using slotted spoon, transfer shrimp to medium bowl. Add remaining 3 teaspoons minced garlic and pepper flakes to skillet and cook until fragrant, about 1 minute. Add flour