1 large, very ripe, fragrant pineapple, peeled, cored, and chopped
1/4 pound butter, melted
1/2 cup brown sugar
3 cups pineapple juice
4 vanilla beans, pods split and seeds scraped out
Salt, to taste

Preheat the oven to 400 degrees F.

Toss the pineapple chunks with the butter and sugar. Place them in a roasting pan and roast for 15 minutes. Shake the pan. Continue roasting, shaking the pan or stirring the chunks every few minutes so they roast evenly, just until the pineapple is lightly caramelized, about another 15 minutes.

Transfer the pineapple to a medium saucepan. Pour the juice into the roasting pan and stir until any remaining bits have dissolved. Pour the juice into the saucepan. Add the vanilla bean pods and seeds. Bring the mixture to a gentle simmer. Simmer until the pineapple softens and begins to dissolve, about 30 minutes.

Discard the vanilla pods. Pur? the sauce in a blender until very smooth. Strain it through a fine-mesh strainer and chill until needed.