1Heat oven to 425°F. Spray cookie sheet with cooking spray. In medium bowl, stir Bisquick mix, cornmeal and milk until soft dough forms. Drop dough into 4 mounds on cookie sheet. Pat each mound into 5-inch round, using fingers coated in Bisquick mix; pinch edges to form 1/4-inch rim. Prick bottoms with fork.
2Bake 8 to 10 minutes or until golden brown. Place on individual serving plates.
3Meanwhile, in 10-inch nonstick skillet, cook turkey over medium-high heat 5 to 7 minutes, stirring occasionally, until no longer pink. Stir in taco seasoning mix and water. Cook uncovered about 5 minutes, stirring occasionally, until thick and bubbly. Spoon turkey mixture onto baked rounds. Top with cheese, lettuce, sour cream and taco sauce.