Preheat Oven: Preheat oven to 325°F (163°C). Do not grease the tube pan.
Prepare Dry Ingredients: In a large bowl, sift together cake flour, 1 cup sugar, baking powder, and salt.
Mix Wet Ingredients: In a medium bowl, whisk together egg yolks, vegetable oil, cold water, vanilla extract, and lemon zest until smooth.
Combine: Pour wet mixture into dry ingredients and mix until just combined.
Whip Egg Whites: In a clean, grease-free bowl, beat egg whites and cream of tartar until foamy. Gradually add remaining ½ cup sugar and beat until stiff peaks form.
Fold in Whites: Gently fold ⅓ of the egg whites into the batter to lighten it, then fold in the remaining whites in two batches.
Prepare Blueberries: Toss blueberries with 1 tbsp flour to prevent sinking, then fold them gently into the batter.
Bake: Pour batter into tube pan, smooth the top, and bake for 55-65 minutes until the cake springs back when touched.
Cool: Immediately invert the pan onto a bottle or wire rack and let cool completely (~2 hours).
Glaze: Mix powdered sugar, lemon juice, and vanilla extract to make a thick but pourable glaze. Drizzle over cooled cake and let set for 10 minutes before slicing.
Serve: Cut using a serrated knife and enjoy!