How to Make It
In a large skillet over medium-high heat, cook bacon in 2 batches, stirring occasionally, until crisp, 10 to 12 minutes per batch. With a slotted spoon, transfer bacon to paper towel-lined plate to drain. Pour off all but 2 Tbsp. fat from skillet. Add onions and garlic; cook, stirring, until onions are translucent, about 10 minutes. Transfer mixture to a 6-quart slow cooker.
Add thyme, vinegar, brown sugar and coffee to slow cooker. Chop bacon into small crumbles, add to slow cooker and stir. Cover and cook on high for 2 1/2 hours. Uncover and cook until onions are caramelized, about 1 hour more. Jam will thicken as it cools.
Let cool. Refrigerate until ready to jar.
GIVE IT Portion the jam into 4 1-cup jars. Cut scraps of fabric with pinking shears and tie over lid with twine. Tie a spreader to the jar with ribbon. The jam will keep in the fridge up to 4 weeks.