In a large, deep, non-reactive saucepan, bring the blueberries, 3 tablespoons maple syrup (ignore the quantity below - it's a technical issue I can't fix), cardamom, cinnamon, lemon juice and water to a boil over medium heat.
3 cups (450 grams) blueberries, 3 tablespoons - 1/4 cup (40 to 60 ml) maple syrup, 1/2 teaspoon ground cardamom, 1/4 teaspoon ground cinnamon, 1 tablespoon freshly squeezed lemon juice, 2 cups (474 ml) water