Step 1

Preheat oven to 325°f / 165°c and arrange a rack in the middle of the oven. Line 1-2 baking sheets with parchment paper (I fitted them all on one half sized sheet but do what you are comfortable with).

Step 2

In a medium bowl, place the granulated sugar and lemon zest. Using your fingers, rub the lemon zest into the sugar until evenly incorporated. Add the melted butter, oil, and lemon juice. Mix to combine, then add the egg and vanilla.

Step 3

Mix well with a whisk or an electric hand mixer until the mixture has thickened slightly and is well combined, 1-2 minutes.

Step 4

Add the flour, baking powder, and salt, and mix until just combined with a spatula.

Step 5

Place granulated sugar and powdered sugar in bowls for rolling.

Step 6

Using a #40 cookie scoop, scoop out balls of cookie dough (approximately 40g per dough ball) and place them into the bowl of granulated sugar (work with one ball of dough at a time). Roll it in the granulated sugar to coat, then shape it into a ball and roll in the powdered sugar (I like to shake the bowl and then give the dough ball a little gentle squeeze to help the powdered sugar stick. Place the dough ball onto the prepared baking sheet.

Step 7

Repeat with the remaining dough balls, arranging on the baking sheet leaving room for spreading. They may flatten a little as you place them onto the baking sheet - do not flatten further.

Step 8

Bake the cookies for 15-16 minutes checking after 14, until the cookies are set around the edges and no longer look soft in the middle of the cookie. The cookies can taste a little gluggy if they are undercooked so just watch the baking time carefully.

Step 9

Remove the pan from the oven and leave to cool on the pan for 10-15 minutes before transferring to a wire rack to cool completely.

Step 10

Store cookies in an airtight container at room temperature for up to 5 days.