3 cups sugar
3 pint baskets (about 9 cups) firm-ripe blueberries, rinsed and drained
1 1/2 cups cider vinegar
Zest (outer peel only, no white pith) of 2 oranges, cut into 3/4-inch wide strips
3 cinnamon sticks (2 inches each), coarsely broken
1 1/2 teaspoons whole allspice
1 teaspoon whole coriander seed
1/2 teaspoon whole cloves
Combine the sugar with 1 1/2 cups water in a large pan. Heat over medium heat to boiling; boil 1 minute. Add the blueberries and return mixture to a boil. Reduce heat to medium-low and cook mixture, uncovered, at a hard simmer just until berries are broken, about 5 minutes. Remove from heat.
Pour berries into a sieve set over a bowl and drain off syrup. Set berries aside for later; return syrup to pan. Add the vinegar, orange zest, cinnamon, allspice, coriander and cloves to syrup and heat to boiling over medium-high heat. Boil mixture, uncovered, stirring occasionally, until syrup is reduced by about half and registers 220 F on a candy-jelly thermometer; this may take up to 50 minutes. Remove from heat.
Meanwhile, if you plan to store relish in jars at room temperature: Wash 3 pint or 6 half-pint jars. Keep hot until needed. Prepare lids as manufacturer directs. If you plan to refrigerate or freeze, wash suitable containers and dry thoroughly.
Strain spices from syrup and discard; return syrup to pan. Add berries and any juices that have accumulated in bowl and heat mixture over medium-high heat to boiling. Reduce heat to medium and cook relish at a simmer, uncovered, for 5 minutes.
For storage in refrigerator or freezer: place in plastic freezer containers or glass jars, cover with tight-fitting lids and refrigerate or freeze.
For long-term storage at room temperature, ladle hot relish into 1 hot jar at a time, leaving 1/4 inch head space. Wipe jar rim with a clean, damp cloth. Attach lid. Fill and close remaining jars. Process in a boiling-water canner for 15 minutes (for 20 minutes at 1,000 to 6,000 feet; for 25 minutes above 6,000 feet).
Serve with smoked pork chops, grilled chicken and roasted duck and turkey. Makes about 6 cups.
— Recipe adapted from "Fancy Pantry," by Helen Witty.