Step 1

You will need an airtight covered plastic container to make the slush in, and to store it in the freezer. Airtight is important because this slush can stay in the freezer for quite a long time if need be, and you don't want it absorbing freezer odours. Large tupperware bowls with snap on lids work well. Here in Newfoundland, if we are making large batches, we use food grade plastic buckets that salt beef is sold in. Don't assume a salt beef bucket in a Newfoundland freezer has salt beef!

Step 2

In any case, this recipe makes about 4 litres/quarts of slush so a 4.5 or 5 litre/quart container will be required.

Step 3

Add the blueberries to a saucepan and bring to a slow simmer for only about 5 minutes to get the berries to release their juice. You can add 1/4 cup of water to the berries if you like, in order to hasten the boiling process.

Step 4

At the same time, in a separate pot, add the 2 cups of sugar to the 2 cups of water and simmer for 4-5 minutes to make a simple syrup.

Step 5

Strain the juice off the berries and add it to a 4 quart (litre) covered plastic container (or larger).

Step 6

Puree the strained berries very well in a blender or food processor.

Step 7

Add the blueberry puree to the plastic container, along with the simple syrup and all of the remaining ingredients.

Step 8

Give it a good stir to combine, put the lid on and put the container in the freezer for about 6 hours.

Step 9

After six hours, ice sheets should be beginning to form in the slush. You want to break these down into smaller crystals. An immersion blender is idea for this, but if you don't have one, a few minutes of vigorous stirring with a whisk should do the trick.

Step 10

Return to the freezer and after a few more hours, give it another stir. The slush then stays covered in the freezer until ready to serve.

Step 11

When serving, stir the slush well every time and spoon 4 ounces of the icy mixture into an 8 ounce glass. Add 2 or more ounces of  club soda. Stir and serve

Step 12

Another suggestion is to serve the slush in martini glasses mixed with a splash of Prosecco and a garnish of a lemon slice and frozen berries on top.