Set a medium-sized saucepan over medium-low heat. Add the butter; once melted, add the onions. Cook for 3-5 minutes, until the onions are fragrant and translucent.
Add the apples, raisins, brown sugar, cinnamon, allspice, vinegar, orange zest and juice, stirring to combine the ingredients. Turn the heat up to medium-high and bring the mixture to a simmer, then turn the heat back down to low and cover.
Simmer for 40 minutes, stirring occasionally. Remove the cover and check the chutney consistency. If it's watery, allow excess liquid to cook off for 3-5 minutes, turning the heat up slightly if necessary. When finished, the chutney should be the consistency of applesauce.
I recommend serving warm apple chutney alongside chicken or pork. Store in an airtight container in the refrigerator and use within 3 weeks.
Notes
Substitutions
You can swap out the yellow onions for shallots (use what you have). Vidalia onions would also work.
You can substitute dried cranberries or cherries for the golden raisins. This won't alter the overall flavor much, but will add a subtle note of whichever fruit you use. Raisins have a more generic flavor. You don't have to use golden raisins if you already have regular raisins in your pantry. I like how the golden raisins blend in and don't speckle the chutney.
Dark brown sugar can be substituted for light brown sugar.