Heat oven to 350° F. Lightly grease a nonstick donut pan, mini muffin or regular muffin pan.
Whisk together flour, sugar, soda, and salt in a bowl; make a well in the center and set aside.
In a separate bowl whisk oil, buttermilk, egg, vinegar, and vanilla together. Pour into the well and mix until smooth and combined. Stir in half the strawberries.