How to Make It
Prepare the topping: Combine strawberries and Prosecco in a medium bowl. Cover and chill until ready to use.
Prepare the streusel: Stir together the all-purpose flour, brown sugar, and cardamom in a small bowl. Add chilled butter, and, using your fingers or a fork, work mixture together until loose crumbs form. Stir in granola. Set aside.
Prepare the cake: Preheat oven 350°F. Stir together cake flour, baking powder, baking soda, and salt in a medium bowl. Combine granulated sugar and softened butter in the bowl of a heavy-duty electric stand mixer fitted with the paddle attachment. Beat on medium-high speed until fluffy. Reduce speed to medium-low, and add eggs, 1 at a time, beating until fully incorporated after each addition. Beat in vanilla. Reduce speed to low. Add cake flour mixture to granulated sugar mixture alternately with sour cream, beginning and ending with cake flour mixture, beating just until incorporated after each addition.
Coat a 12-cup Bundt pan with baking spray. Scrape half of batter into prepared pan. Set aside 2 tablespoons streusel; top batter evenly with remaining streusel. Top evenly with remaining batter, and sprinkle with reserved 2 tablespoons streusel. Bake in preheated oven until a wooden pick inserted in center of cake comes out with moist crumbs, 45 to 50 minutes.
Cool cake in pan on a wire rack for 15 minutes. Invert cake onto a serving plate and cool completely, about 1 hour.
Prepare the glaze: Combine strawberries, corn syrup, and Prosecco in a small saucepan. Bring to a simmer over medium-high, stirring often. Reduce heat to medium, and simmer, whisking occasionally, until thickened and strawberries have broken down. Stir in cornstarch, and simmer 1 minute. Remove from heat, and cool slightly, 12 to 15 minutes.
Spoon glaze evenly over the cake. Remove topping from the refrigerator, and top the cake with 8 of the Prosecco-soaked strawberries and ½ cup granola. Serve the cake with remaining Prosecco-soaked strawberries.