- 1/2 large watermelon
- 100 grams caster sugar
- 70 millilitres Tequilla
- 30 millilitres Cointreau
- 2 limes, juice only
- Put the watermelon half into your biggest mixing bowl and use an electric hand whisk on its lowest setting to blitz the inside to a pulp. Be warned - it’s messy! Quite a lot of the watermelon will end up in the bottom of the bowl, don’t worry about that for a minute. Add the sugar, Tequilla, Cointreau and lime juice into the watermelon shell and mix through with a fork.
- Twist a tea towel into a long rope and shape it into a circle on a baking tray that is big enough to hold the watermelon, but small enough to fit in your freezer. Prop the watermelon up inside the tea towel then fill it to the top with leftover juice from the mixing bowl. Put it into the freezer for 2 hours then use a fork to scrape and mix up the frozen parts. Repeat every hour until the juice has all turned into a frozen granita - depending on the size of your watermelon this could take 4-5 hours. After the first 3 churnings the watermelon should be fine to rest in the freezer overnight so you can always make ahead and finish on the day you need it.
- Serve straight out of the watermelon or in martini glasses with a wedge of lime.