1. Preheat oven to 350°F. Grease 12-cup Bundt pan. Sprinkle evenly with 1 tablespoon of the sesame seed. Pour 1/3 cup of the root beer into 1-quart saucepan. Set aside.
2. Prepare cake mix as directed on package using remaining root beer in place of the water and adding remaining 1 tablespoon sesame seed to the batter. Pour batter into prepared pan.
3. Bake 40 to 45 minutes or until toothpick inserted into cake comes out clean. Cool in pan 15 minutes. Invert cake onto wire rack. Cool completely.
4. Meanwhile, bring root beer in saucepan to boil on high heat. Reduce heat to low; simmer 4 to 5 minutes or until reduced by half (2 to 3 tablespoons). Cool to room temperature. Mix confectioners’ sugar and 4 to 5 teaspoons of the reduced root beer until glaze is of desired consistency. Immediately drizzle over cooled cake. Let stand until glaze is set.
Test Kitchen Tip: If using McCormick® Gourmet Collection Sesame Seed, first toast is a small skillet on medium heat 2 minutes or until fragrant and golden brown. Immediately pour out of hot pan to avoid over-toasting.