1. Cut 2 pounds of bacon into 1-inch pieces and cook over medium-high heat in a large skillet, stirring occasionally, until bacon is browned, about 20 to 30 minutes. Drain grease, reserving ¼ to ½ cup, and place bacon on paper towels to drain.
2. Return the reserved bacon grease to the pan along with 2 diced medium, yellow onions; cook until caramelized, 30 to 35 minutes. Add 2 minced garlic cloves, ¾ cup strong black coffee, ½ cup maple syrup, ½ cup coconut sugar, ½ cup apple cider vinegar, and ¼ teaspoon red pepper flakes, and simmer for 5 minutes.
3. Add the bacon and simmer on low for 2 ½ to 3 hours or until mixture thickens. Transfer to a food processor and briefly pulse until coarsely chopped. Cool and refrigerate for up to 1 week. (Makes 3 cups.)
—Embedded images by Peter James Field