Preheat oven to 350 F and prepare a mini donut pan.
In a medium bowl combine flour, baking powder and baking soda. Set aside.
In a separate bowl whisk the eggs, add oil, butter, vanilla extract, buttermilk and sugar. Combine well with a wooden spoon.
Add flour to wet ingredients.
Pour the batter into the bag, make a small hole on the corner. Push gently the batter into the baking pan and form mini donuts.
Bake for 12 - 15 minutes.
Cool off before glazing on the wire rack.
Place strawberries in the blender and make puree. Transport puree into the small saucepan and heat for minute on low heat. Add powdered sugar and whisk vigorously. Transfer into the bowl. Set aside to cool off for two - three minutes.
Dip each donut into the bowl and place on the wire rack.
* Any oil can be used ** If the glaze is to watery add more powdered sugar. It depends how large are strawberries and if they contain lots of water. They may need less or more powdered sugar.