Add the table sugar and the dextrose to a deep saucepan.
Add the Locust Bean Gum to the saucepan. Unless you have specialized scales, it will be difficult to weigh 3 grams accurately. So, 3 grams is about the same as 1 ¼ compact teaspoons.
Use a fork to thoroughly mix the dry ingredients. This part is really important. If the Locust Bean Gum isn’t thoroughly mixed into the rest of the dry ingredients before you add the milk, it won’t work properly.
Add the milk to the saucepan and warm over a medium heat, stirring all the time to dissolve the dry ingredients.
Keep stirring and checking the temperature with a digital cooking thermometer until the mixture reaches 185° F / 85° C.
Remove from the heat and allow to cool to about 149° F / 65° C.
Then add the cream and blitz for a couple of minutes with a hand blender.
Transfer to a bowl and when the mixture stops steaming, cover with cling film and allow it to cool to room temperature.
Put the bowl in the fridge until it the mixture cools to at least 45° F / 7° C. You’ll get the best results if you leave it overnight.
Place the container that you’ll use to store the ice cream in the freezer. This will pre-chill it, so it’s less likely to melt the ice cream when you’re transferring it from the machine to the freezer.
Spinning the ice cream
Remove the mixture from the fridge and give it another quick blitz with a hand blender.