Preheat oven to 300°F. Prepare Old Country Kitchenware square tube pan by brushing with pan coat and adding a parchment paper square between the two pieces.

Beat butter and sugar in the bowl of a stand mixer until pale, light and fluffy.

Add ½ cup flour, salt, and vanilla extract and beat until combined. Scrape the bottom and sides of the mixing bowl.

Add 1 egg and beat for 30 seconds. Repeat with each egg, beating well after each addition.

Add sour cream and beat to combine.

Add the rest of the flour in 2 additions, beating on low until it just disappears. Scrape the bottom and sides of the bowl and beat for another 15 seconds.

Pour about a 1” layer of batter into prepared pan.

Rinse blueberries, and while they’re still damp, toss them in ¼ cup flour.

Gently fold in blueberries to the remainder of the batter.

Pour batter into prepared tube pan. Place on middle rack of oven with a baking sheet on the rack below it to catch any drips.

Bake 2 ½ hours to 2 ¾ hours or until a skewer inserted into the cake comes out clean.

Let cool 15 minutes. To unmold, place over a metal can and push down to remove outer piece.

When cool enough to handle, lift or turn cake out onto a wire rack and let cool completely.

For the lemon glaze, sift powdered sugar into a bowl and add 2 tbsp lemon juice. Beat with an electric mixer.

Add lemon juice a tiny splash at a time until desired consistency. If a thicker icing is desired, add more powdered sugar, one tablespoon at a time. If a thinner icing is desired, add more lemon juice or water, one teaspoon at a time.

Slowly pour over cooled cake.