How to Make It
Prepare the cake: Preheat oven to 350°F. Coat a 10-cup Bundt pan with baking spray. Stir together flour, baking powder, baking soda, and salt in a bowl. Place eggs, sugar, and oil in bowl of a stand mixer fitted with a paddle attachment. Beat on medium-high speed until light and airy, about 3 minutes, stopping to scrape down sides as needed. Stir in squash, lemon zest, and juice. Gradually add flour mixture, beating on low speed until just combined, about 45 seconds. Pour batter into prepared pan.
Bake in preheated oven until a wooden pick inserted in center comes out clean, 50 to 55 minutes. Cool in pan 10 minutes. Invert onto a wire rack; cool 1 hour.
Prepare the glaze: Whisk together all ingredients in a bowl until smooth. Drizzle over cooled cake.