Remove the garlic from the bulb and squeeze the softened garlic cloves into a medium bowl. Add the olive oil and diced onion to the garlic cloves and mash with a fork until smooth. Stir the lemon juice into the mashed garlic and continue stirring until smooth and creamy. Add seasonings and salt.
Place in the refrigerator for 2 hours before serving to let the herbs infuse into the jam. The garlic jam will keep refrigerated in a sealed container for up to 2 weeks. Serve with sliced bread, crackers or toast.