1. In a large bowl, add two-third cups of white granulated sugar and zest from one lemon. Mix with a spatula and press on the sugar and zest to extract oil from the zest. Do this until the mixture turns slightly yellow in color.

2. Use a mixer and add two eggs at room temperature. Add half a cup of vegetable oil gradually while mixing. Then add half a cup of buttermilk and one tsp of vanilla extract and continue to mix.

3. Sift one and three-quarters of all purpose flour, two tsp of baking powder and one-quarter tsp of salt. Mix the dry ingredients together and add to the wet mixture and whisk just until combined. A few traces of flour is fine which will blend with the mixture once we add in the blueberries since we do not want to overwork the mixture.

4. Finally stir in 2 cups of blueberries to the mixture with a spatula.

5. Place two scoops of the mixture into each cup of a muffin tray fitted with cupcake liners. Preheat oven to 375 F.

6. Create the topping by combining three tbsp of white granulated sugar, one-quarter cup of all purpose flour and 2 tbsp of melted butter. Once mixed together to create flaky lumps, spread them over each muffin mixture on the tray.

7. Place the tray in the oven at 375 F for 25 mins. Let the muffins cool for 30 minutes before serving.