In a frying pan over medium-high heat, cook bacon until crispy. Remove bacon from pan, reserving 2 tbsp of bacon fat.
On medium heat, sauté onion in reserved bacon fat until just tender, about 3 minutes. For the liquids, the magic happens when you add the first liquid and cook just until thickened before adding the next liquid. Add maple syrup and cook 3-5 minutes, then add vinegar and cook for 3-5 minutes; add tomatoes and cooked bacon; cook until thickened. Let cool and add fresh tarragon. Delicious served hot or cool.
Makes 2 cups (500 mL)