Bakery Style Blueberry Muffins

Preheat oven to 425 degrees F.
In a large bowl, combine melted butter, sugar, brown sugar, and vegetable oil. Whisk together and then add eggs, greek yogurt, vanilla extract, and whole milk. Whisk together until all clumps are gone and mixture is smooth.
In a separate bowl, whisk together flour, baking powder, baking soda, and salt. Add blueberries, ensuring all blueberries are coated in flour.
Add flour mixture to the wet ingredients and fold the two together with a spoon/spatula. Mix together until flour is completely mixed in with wet ingredients, about 30 seconds. Cover batter with a towel or plastic wrap and allow batter to rest for 15 minutes.
Line a jumbo muffin pan or regular muffin pan with cupcake liners/baking cups. Fill each baking cup to the top with batter. Sprinkle demerara sugar on top (optional).
For jumbo muffin pan, bake at 425 for 5 minutes and then reduce heat to 350 degrees and continue to bake for 25 minutes. For a regular size muffin pan, bake for at 425 degrees for 5 minutes then reduce heat to 350 and bake for another 15-18 minutes, until a toothpick comes out clean.