Heat oven to 350 degrees. Lightly grease a 9x13-inch baking pan. In small bowl, combine flour, baking powder, cream of tartar and salt. Set aside.
In large bowl, beat butter with electric mixer on high speed until creamy. Beat in sugars. Beat in eggs and vanilla until combined. Gradually mix in dry ingredients until combined.
Spoon half of the batter into the prepared pan and spread evenly. In a small bowl, combine ingredients for cinnamon filling. Dollop cinnamon-sugar mixture evenly over batter.
Spoon remaining batter evenly over cinnamon-sugar mixture. Swirl slightly with a sharp knife to create a marbled effect.
Bake for 20 to 25 minutes or until golden brown and toothpick inserted in center comes out clean. Cool completely before adding glaze, about 1 hour.
In small bowl, whisk together glaze ingredients until smooth and thin enough to drizzle. Drizzle over bars then cut into squares to serve.