In a large bowl whisk together the dry ingredients (flours, sugar, salt, baking powder and baking soda). In another bowl, lightly beat eggs. Add buttermilk, oil and vanilla and whisk until blended. Pour the buttermilk mixture into the flour mixture and stir until a batter forms and no flour is visible. Lumps are ok.
Heat a non-stick frying pan over medium heat and brush with a little oil. Pour ¼ cup of batter per pancake onto heated pan. Press several blueberries per pancake into the pancake batter. Cook pancakes until bubbles appear and edges look slightly dry (1-2 minutes). Turn pancakes and cook until golden brown on other side and cooked through (no raw batter in the middle or near the blueberries). Keep pancakes in a warm oven (175°F or 80°C) until all the batter is used up.
Serve pancakes warm with butter and maple syrup, your choice of jam or whipped cream. Freeze leftover pancakes between layers of parchment or wax paper and reheat for 1 minute in microwave.