Granny Fearing's Baked Beans

• 1 onion
• 1/2 thickly smoked bacon (sliced)
• 600 gr pork
• 300 ml bottle ketchup
• 280 gr packed brown sugar (light)
• 120 ml sweet gherkin juice
• 60 ml molasses
• 16 ml mustard (yellow)
• 5 ml apple cider vinegar