Blueberry-Coriander Jam

Toast coriander seeds in a saucepan over medium, stirring occasionally, until fragrant and golden, 3 to 6 minutes. Remove from pan; let cool about 5 minutes. Using a mortar and pestle or spice grinder, grind into a fine powder.

Cook blueberries, sugar, lemon zest and juice, and ground coriander in the same saucepan over medium-high, stirring occasionally, until slightly thickened and reduced to about 1 3/4 cups, 10 to 12 minutes. Stir in salt to taste.

Reserve 3/4 cup jam for decorating cake; set aside. Pour remaining 1 cup jam through a fine wire-mesh strainer, pressing firmly with the back of a spoon to yield about 3/4 cup strained jam. Let cool completely, about 2 hours.