Combine the blueberries, lemon juice, sugar, and salt in a saucepan. Bring to a boil, then reduce the heat and simmer for 10 minutes. The compote will thicken, especially after it cools. If you want it thicker, add the arrowroot powder and stir until dissolved.
Recipe by The "V" Word at http://thevword.net/2016/05/product-review-sirabellas-vegan-cheesecake.html