Heat the oven to 350°F. Sift all-purpose flour, cake flour, baking powder, and salt in a large bowl. Set aside.
Mix sugar and lemon zest in a food processor or high-speed blender. Pulse several times to distribute zest. Pulse in lemon juice, eggs, and sour cream.
Slowly pour in the melted and cooled butter on low speed until well combined. Create a well in the dry ingredients. Put wet ingredients in.
Mix gently with a rubber spatula until combined. Slightly thin batter. Grease a 10 or 12-cup bundt pan with Baker's Joy or melted shortening.
Spread the spray throughout the pan with a pastry brush. Put batter in immediately. Bake for 50–60 minutes until a toothpick inserted into the center comes out clean or with a few moist crumbs.
After 15–20 minutes, run a thin flexible knife around the edges and invert onto a wire rack. Cool completely.
Mix glaze ingredients in a small bowl until thick but pourable. Add juice, milk, or sugar to thin or thicken. Cover cake and drip if desired. Slice and serve 15 minutes later.The glazed cake can be kept at room temperature for 2 days in foil or plastic.
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