Preheat the oven to 425°F. Lightly spray a 12 cup muffin tin with non-stick spray, or line it with paper liners and set aside.

In the bowl of a food processor, combine the sugar and lemon zest until the lemon zest is finely chopped and the sugar is fragrant and light yellow in colour.

Add the lemon juice, eggs, melted butter, and oil and process until well combined.

Add the milk and vanilla and process again.

In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and poppyseeds.

Make a well in the flour mixture, pour in the liquid mixture, and stir until just combined.

Scoop the muffin batter into the prepared muffin tin, dividing it between the 12 muffin cups.

Sprinkle the tops with coarse or turbinado sugar if desired.

Bake for 5 minutes, then lower the oven temperature to 350°F and continue baking for 14-17 minutes, or until a toothpick inserted in the center of a muffin comes out clean.

Allow the muffins to cool for 5-10 minutes in the muffin tin, and then remove them to a wire rack to cool completely.