Combine plums, garlic, brown sugar, vinegar, water, salt, ginger, allspice, pepper, cayenne and cinnamon stick in a large heavy saucepan. Bring to a simmer, stirring frequently. Reduce heat to low and simmer, uncovered, stirring occasionally, until the plums have cooked down to a puree, 35 to 45 minutes. Remove from heat and let cool. Discard the cinnamon stick. Transfer to a bowl or storage container.Advertisement
Make Ahead Tip: Cover and refrigerate for up to 1 week or freeze for up to 6 months.