Position oven rack in center of oven and preheat oven to 350°F. Line 9”x5”x3” loaf pan with strips of parchment paper (one strip horizontally across the pan and one strip vertically down the length of the pan), leaving enough paper overhang with which to grasp and lift the baked loaf to remove it from the pan. Spritz parchment-lined pan very lightly with cooking oil.
In bowl of stand mixer fitted with paddle attachment and on low speed, combine the vegetable oil, melted butter, and sugar. Beat at medium speed until combined. Add the eggs, one at a time, beating slightly after each egg has been added. Blend in the sour cream followed by the vanilla. Stop mixer, as necessary, to scrape bowl with rubber spatula to ensure the ingredients are evenly incorporated. Beat entire mixture about 15-20 seconds at medium speed.
With mixer on lowest speed, add the flour mixture in three parts alternately with the milk-juice mixture, starting and ending with the dry ingredients (three additions of dry ingredients with two additions of wet ingredients). Periodically stop mixer and scrape sides of bowl with spatula to ensure all ingredients are combined. Increase speed to medium low and beat mixture 15-20 seconds to ensure ingredients are incorporated. Do not overmix.
Remove bowl from mixer stand and gently fold in half of the blueberries. Transfer three-quarters of the batter to the prepared pan, smoothing batter evenly with a knife. Sprinkle remaining blueberries over batter. Spread remaining batter over the blueberries and smooth with a knife.
Yield: One loaf, 14 slices (sliced approximately ½” thick)
Notes: Loaf is best made the day before it is needed. Let cool completely on wire rack then place in airtight plastic bag and store in refrigerator overnight to allow the flavours time to blend and loaf time to set. Loaf freezes well, either whole or sliced into individual slices.