Sweet and tender Blueberry Cake! This is made with frozen blueberries so you can enjoy this tempting treat year round! It has a moist and delicious crumb and a perfectly satisfying flavor. Perfect for a weekend breakfast or after dinner dessert.
Preheat oven to 350 degrees. In a mixing bowl whisk together 1 3/4 cup of the flour, the baking powder, baking soda and salt. set aside.
In the bowl of an electric stand mixer fitted with the paddle attachment, whip butter, granulated sugar and 1 Tbsp vegetable oil on medium-high speed until pale and fluffy. Stir in remaining 2 Tbsp vegetable oil.
Blend in eggs one a time, mixing until combined after each addition and adding in vanilla with second egg. In liquid measuring cup used to measure buttermilk, whisk together buttermilk and sour cream.
Working in three separate batches add 1/3 of the flour mixture and mix just until nearly combined, then alternate with buttermilk mixture and mix just until nearly combined, repeat once more then end with flour mixture mixing just until combined.
Toss frozen blueberries with remaining 2 Tbsp flour then fold into batter.
Pour batter (it will be very thick and cold) into a buttered 8 by 8-inch baking dish and spread into an even layer and sprinkle top evenly with raw sugar.
Bake in preheated oven 55 - 60 minutes, or until toothpick inserted into center of cakes comes out free of batter and tent cake with foil near last 15 minutes of baking to prevent excessive browning of top. Allow cake to cool on a cooling rack then cut into squares. Store in an airtight container.
*Fresh blueberries would work fine too. If using fresh reduce the baking time by about 10 - 15 minutes.