Pre-heat the oven to 375 degrees F.
Fill a 12 well muffin tray with muffin liners, or spray the muffin wells with non-stick cooking spray.
In a medium bowl, whisk together the flour, cornstarch, baking powder and salt.
In a larger bowl attached to stand mixer or with a hand held beater, beat the butter, oil and sugar for two minutes, until creamy.
Add the eggs one at a time, making sure that you are scraping down the sides of the bowl and beating well after each addition.
Beat in the vanilla and almond extract.
Gradually add the flour mixture and milk, alternating between the two, mixing on low speed the entire time to combine.
Fold in the blueberries until mixed throughout the batter evenly.
Divide the batter evenly between the muffin wells - they will be full! I like to use a cookie dough scoop or an ice cream scoop with a wire scraper inside to get nice, rounded muffin tops.
Sprinkle some finishing sugar on top of the muffins.
Bake for 20-25 minutes, until the tops are beautifully browned and the top springs back when touched. If you have one, insert a cake tester to make sure that they are done.
Remove from the oven and cool.