THIS is a variation on a traditional sweet-spicy sauce. Baste it on ribs in the last 10 minutes of cooking. For colour, and to make flavour pop, before serving, sprinkle a little with orange zest on top. 

Makes 2 cups

¾ cup sugar
½ cup water
¾ cup unseasoned rice wine vinegar
½ cup tomato paste
¼ cup fresh orange juice
2 tbs unsweetened cocoa powder
1 tbs Worcestershire sauce
½ tsp vanilla extract
½ tsp kosher salt
Pinch of chipotle powder

Combine the sugar and water in a medium saucepan over low heat. 
Cook, stirring, until the sugar has dissolved, then add the vinegar, tomato paste, orange juice, cocoa powder, Worcestershire sauce, vanilla extract, salt and chipotle powder, stirring to combine. 
Cook for 30 minutes, stirring occasionally, then cool to room temperature before using or storing.

The Washington Post