Pumpkin Bundt Cake

3 cups Original Bisquick® mix
1 cup granulated sugar
1 cup packed brown sugar
1/4 cup butter or margarine, softened
2 1/2 teaspoons pumpkin pie spice
1/4 cup milk
4 eggs
1 can (16 ounces) pumpkin (not pumpkin pie mix)
1 cup powdered sugar
1 tablespoon milk
1/2 teaspoon vanilla

Heat oven to 350°F. Grease and flour 12-cup fluted tube cake pan.
Beat Bisquick, granulated sugar, brown sugar, butter, pumpkin pie spice, 1/4 cup milk, eggs and pumpkin in large bowl on low speed 30 seconds. Beat on medium speed 3 minutes. Spread in pan.
Bake about 50 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes; turn upside down onto heatproof plate or wire cooling rack. Remove pan; cool cake completely.
Stir remaining ingredients until smooth and thin enough to drizzle. Drizzle over cake.