Preheat oven to 350 ° F. Prepare 6-inch spring form pan by spraying with baking spray.
In a medium bowl or mixer bowl, cream the oil, butter, and sugar together on high speed for 3–4 minutes until light and fluffy. Add the eggs, one at a time making sure they are completely incorporated until adding the next. Add the vanilla, lemon juice and zest, and mix well.
In a large bowl, sift together 1 ½ cups flour, baking soda, baking powder, and salt. Add the wet ingredients into the dry and mix just until combined, making sure to scrape the bottom and the sides of the bowl.
Toss the blueberries in 1 tablespoon of flour and fold into the batter. Pour batter into spring form pan.
Bake for 45 minutes or until a toothpick or knife inserted into the center of the cake comes out clean.
Let cool. Make the glaze by mixing the powdered sugar, lemon extract, and milk together. Pour over top of slightly warm cake.