Fresh pineapple and mango team up to make a lively chutney with a nice balance of spicy and sweet. Serve with pork, chicken or duck, or add a few tablespoons to your favorite curry. This chutney can be made with pineapple alone if mangos aren't in season; canned, unsweetened pineapple chunks will also work, but reduce the cooking time.
Place the vinegar, agave syrup, brown sugar, vanilla, cinnamon, star anise and ground cloves in a medium-size saucepan and set over medium heat. Bring the mixture to a simmer, stirring to dissolve the sugar. Add the pineapple, mango, ginger, garlic, Serrano pepper and salt, and cook over low heat until the fruit is tender but not mushy, 20 to 25 minutes.
Remove the pan from the heat and let the chutney cool at room temperature. Discard the pieces of cinnamon and the star anise pod. Stir in the mint, if using.
Serve the chutney at room temperature or transfer to a clean container, cover and refrigerate for up to 3 weeks.