Sauté shallots and onions with duck fat, salt, pepper and chili flakes for about 10 minutes, or until just beginning to caramelize (over medium heat). Add beer, sugar, honey, vinegar and fruit and cook at a simmer until the fresh blueberries have ruptured, the dry blueberries are plumped and the liquid in the pan is getting thick like syrup. Transfer the mixture to glass jar(s) and lid it while it is hot. Cool it on your kitchen counter until room temp, then refrigerate. Keeps for 4 weeks chilled.