Preheat the oven to 400 degrees F (200 degrees C). Line a muffin tin with 9 paper liners.
Whisk milk, olive oil, and egg together in a large bowl until well combined; mix in flour, sugar, and baking powder. Fold in blackberries until incorporated. Divide batter among the prepared muffin cups, filling each ½ full.
Bake in the preheated oven until a toothpick inserted into centers comes out clean, about 20 minutes.
Wild Blackberry Muffins · Dinner Match Lab | Dinner Match Lab