How to Make It
Prepare the Cake: Preheat oven to 300°F. Coat a 14-cup Bundt pan with baking spray. Beat butter, cream cheese, and sugar with a stand mixer fitted with a paddle attachment on medium speed until fluffy, 3 to 5 minutes. Gradually add eggs 2 at a time, beating well after each addition. Beat in lemon zest, lemon juice, and vanilla until combined. Gradually add flour; beat until smooth, about 30 seconds. Fold in blueberries. Transfer batter to prepared Bundt pan.
Bake in preheated oven until a wooden pick inserted in center of cake comes out clean, 1 hour, 30 minutes to 1 hour, 40 minutes. Let cool in pan 30 minutes. Invert onto a wire rack; let cool completely, about 1 hour, 30 minutes.
Prepare the Glaze: Stir together blueberries, water, and granulated sugar in a small saucepan; bring to a boil over medium-high, stirring often. Reduce heat to medium-low; simmer, stirring often, 2 minutes. Pour mixture through a fine mesh strainer into a heatproof bowl; discard solids. Let mixture cool completely, about 30 minutes.
Stir together powdered sugar, lemon juice, and 2 tablespoons of the strained blueberry juice in a medium bowl, adding additional blueberry juice 1 tablespoon at a time until desired consistency is reached. Spoon Glaze over cooled Cake. Let stand until Glaze is set, about 30 minutes.