Step 1

Preheat the oven to 325°f / 165°c. Line a baking sheet with parchment paper.

Step 2

Fit a large sturdy piping bag with a large open star tip of your choice - I used an ateo #

Step 3

In a medium bowl using an electric hand mixer, or in the bowl of a stand mixer fitted with the paddle attachment, whip together the butter, powdered sugar, and vanilla on medium to high speed until light and fluffy, stopping to scrape down the bowl once or twice during the process to ensure it is well mixed.

Step 4

Add the flour and corn starch, and mix with the mixer to just incorporate. Add in the heavy cream, and mix again to combine.

Step 5

Transfer the mixture to the piping bag - I find the best way to do this is to put the piping bag into a glass jar or deli container and fold the edges over the sides of the glass to give an opening. Use a bench scraper or something similar to push all the mixture to the end of the piping bag. Secure the end with a clip if desired.

Step 6

If you would like, use a tiny bit of the batter to hold your parchment paper down on each corner to stop it from moving as you pipe.

Step 7

Pipe out the cookies - I did three rows of five cookies. Pipe each into a rosette - hold the piping bag straight up and down, then using even pressure, pipe a circle of dough until it loops back onto itself, finishing with a little flick of the wrist. The rosettes should be about 4.5cm in diameter but this will depend on the size of your piping tip.

Step 8

Leave a little room for spreading. Repeat with the rest of the cookies. If you are not happy with one, just scrape it off the parchment paper and pop it back into the bag and try again.

Step 9

Once all of the cookies have been piped out, sprinkle with granulated sugar if using, then transfer to the oven. Bake for 13-14 minutes, until the cookies are set and lightly golden brown around the edges. If you like a more golden brown and crunchy cookie, increase the cooking time slightly.

Step 10

Remove from the oven, and if you put sugar on them before the oven, give them another coating hot from the oven.

Step 11

Leave to cool on the pan for 15-20 minutes then transfer to a wire rack to cool completely.

Step 12

Store butter cookies in an airtight container at room temperature for up to a week.