Yes, you can use frozen blueberries. Just be sure to thaw and drain the excess liquid off them before using them in this blueberry crisp recipe. Can I make this recipe without gluten-free flour ...
For this recipe, you will need a sugar thermometer ... For the blackcurrant mousse, add the frozen mixed berries to the pan of cooked berries, pour over 50ml/2fl oz water and bring the mixture ...