
Combine butter and canola oil in a large bowl and whisk until well-combined.
Add sugar and whisk to combine.
Add egg, egg white, and vanilla extract. Whisk vigorously, until all ingredients are thoroughly combined.
Gradually whisk in buttermilk until completely combined.
In a separate bowl, whisk together flour, baking powder, corn starch, and salt.
Fold the dry ingredients into the wet gently, taking care not to over-mix the batter. Once about half of the dry ingredients have been combined, add your chopped strawberries and continue to gently stir until ingredients are just combined.
Optional, but recommended: Cover bowl with a dry towel and allow the batter to rest for 30-60 minutes before proceeding (see "resting note" below for more info). Meanwhile, preheat your oven.
Preheat oven to 425F (215C) and line a 12-count muffin tin with paper liners.
Once oven has preheated, evenly divide batter into prepared tin (note: this recipe will make 12 muffins, but for bigger/bakery style muffins i recommend dividing the batter into only 9 muffin liners!).
Sprinkle a small bit of sugar over the top of each muffin.
Transfer to center rack of 425F (215C) preheated oven and bake for 8 minutes and then (without opening the oven door) reduce the oven temperature to 350F (175C) and bake another 10-12 minutes, or until tops are just beginning to turn golden brown.
Allow muffins to cool in their tin for 5-7 minutes then carefully remove from muffin tin and transfer to cooling rack to cool completely before enjoying.