Using an electric mixer, start by creaming the softened butter together with the sugar. Beat until the mixture is light and fluffy.
Add the eggs, one at a time, mixing each one into the batter thoroughly. Add the vanilla and mix again.
Add the dry ingredients to the batter, adding a little at a time, and alternating with the sour cream. I started with 1 cup of flour, then added half the sour cream, added another 1/2 cup of flour, the rest of the sour cream, and finished with the last of the flour.
Before you add the blueberries to the batter coat them in flour. Add 1-2 tablespoons of flour to the berries, and toss them with your fingers to completely coat them with flour. When that's done, fold them carefully into the cake batter with a rubber spatula to keep them from breaking open.
Pour the batter into a greased and floured 9 X 13 inch pan, and bake for 30-35 minutes at 350°, or until the cake is brown on top and a toothpick inserted in the center comes out clean. Cool completely before cutting.
Find this recipe at https://mymommyworld.com/blueberry-sour-cream-cake-recipe/