Sweat the onion in a large saute pan over medium heat then add the pineapple, jalapeno peppers, ginger, walnuts and crushed piri-piri peppers. Continue cooking, stirring often, until warm and fragrant, about 3 minutes.
Add the vinegar, honey, salt, cinnamon, nutmeg and cloves and bring to a simmer. Lower the heat and cook on low for 60 to 75 minutes, until the liquid is completely evaporated and the pineapple is translucent.
Remove from heat and allow to cool to room temperature, then transfer to clean air tight containers and store in the refrigerator for up to a couple of weeks.
This chutney will taste better after the flavors have had time to meld for a few days.
Serve with your favorite meat or fish, use to garnish sandwiches and hamburgers, add a few spoonfuls to sauces and vinaigrette for instant flavor boost, or try it over vanilla ice cream!