Heat oven to 325°F. Generously grease 12-cup fluted tube cake pan with shortening. In small bowl, mix 3 tablespoons granulated sugar and 1 teaspoon cinnamon; sprinkle evenly over shortening to coat pan.
In large bowl, beat 1 cup sugar and the butter with electric mixer on medium speed until light and fluffy, scraping bowl occasionally. Add 1 egg at a time, beating well after each addition. Beat in sour cream.
On low speed, beat in 2 cups flour, the baking powder, baking soda, 1/2 teaspoon cinnamon and the salt. Coat blueberries with 2 tablespoons flour. With spoon, gently stir blueberries into batter. Spoon batter into pan.
Bake 45 to 50 minutes or until toothpick inserted near center comes out clean. Cool upright in pan on cooling rack 25 minutes. Place heatproof serving plate upside down over pan; turn plate and pan over. Remove pan. Cool cake completely, about 1 hour.
In small bowl, mix powdered sugar, maple flavor and enough milk until smooth and desired drizzling consistency; drizzle over cooled cake.