Cut tomatoes into smaller pieces and make a green tomato puree using a blender. Add tomatoes little by little.
If your tomatoes have seeds and rough peel, strain the puree through a sieve (mine were perfect, no seeds and soft peel so I didn't need to strain).
Pour the tomato juice into a roomy saucepan bring to a boil. Turn the heat on low and simmer until you get left with half the juice.
Pour sugar and continue simmering until you get a medium thick syrup
Meanwhile dice the apples. Alternatively you could grate the apples or pass them through a blender if you want your jam to have a smoother texture or you don't like to feel apple chunks in your jam. This method will also help you spread the jam easier on toast.
Grate the lemon, set it aside and squeeze the lemon juice out.
Sprinkle the lemon juice on the apples. This will prevent the apples from browning until the tomato syrup is done
When the tomato syrup is dense enough, add the apple cubes, the cinnamon sticks and the lemon zest
Keep simmering until all apple cubes get a glassy texture.