For the artichokes: Remove 3 strips of zest from lemon. Cut lemon in half. Trim stems from artichokes to stand; remove loose outer leaves. Cut about 1 inch off the top of each artichoke; snip off sharp leaf tips. Rub cut edges of artichokes with a lemon half to prevent browning.
In a 3½- or 4-qt. slow cooker place artichokes, stem ends down. Pour 1 cup water around artichokes. Squeeze lemon halves over artichokes. Sprinkle artichokes with garlic, salt, and pepper. Drizzle with oil. Add lemon strips and thyme sprigs. Cover and cook on low 6 to 7 hours or high 3 to 3½ hours or until a leaf easily pulls out of artichoke. Using a slotted spoon, transfer artichokes to a platter. Drizzle with 2 Tbsp. Bagna Cauda Sauce. Sprinkle with snipped thyme. Serve with remaining sauce.
For the optional bagna cauda sauce: In a small saucepan combine 1½ tsp. minced garlic; 3 Tbsp. olive oil; 2 Tbsp. butter; 2 canned anchovies, minced (2 tsp.); and ¼ tsp. crushed red pepper. Cook over low heat 5 minutes or until sauce begins to bubble. Remove from heat. Makes ⅓ cup sauce.