Prepare foil handles by tearing off three 18-inch by 2-inch strips of heavy foil (or use regular foil folded to double thickness). Crisscross foil strips in a spoke design; place in your Crock-Pot® slow cooker.
Coat slow cooker with butter or nonstick cooking spray.
Blend ¼ cup baking mix, brown sugar, and cinnamon in a small bowl and set aside.
Combine remaining 1 ½ cups baking mix, granulated sugar, yogurt, egg, and vanilla in a medium bowl and mix until blended.
Spoon half of batter into slow cooker. Sprinkle half of cinnamon sugar mixture over top. Repeat with remaining batter and cinnamon-sugar mixture.
Line lid with two paper towels and cover tightly. Cook on HIGH for 1 ¾ to 2 hours or until toothpick inserted into center comes out clean and cake springs back when gently pressed. Turn off heat; let stand for 10 minutes. Remove cake to large serving platter using foil handles.
Whisk milk into powdered sugar, 1 tablespoon at a time, until desired consistency.
Spoon glaze over top of cake. Cut into wedges, serve, and enjoy!
