1 Large marrow
4 Tablespoons of water
3 Tablespoons of lemon juice (1 Lemon)
4oz Crystallized ginger (chopped)
1 Bottle Certo
Peel the marrow, discarding the skin and seeds and cut up finely.
Add the water and simmer, covered, for 20 minutes.
Put the sugar, prepared marrow, lemon juice in a muslin bag.
Now put the crystallized ginger and the muslin bag into the pan.
Mix well and heat slowly until the sugar has dissolved, stirring occasionally.
Bring to full rolling boil, and boil for 2 minutes.
Remove from heat and take out the muslin bag.
Stir in the Certo.
Allow to cool to prevent fruit floating, then ladle into clean, dry, warmed jars, filling them to the very top. There will be some shrinkage.
Cover immediately with a waxed disc, placing the wax side downwards and smoothing the disc on to the surface of the jam, so that air bubbles are trapped between the disc and jam. Tie covers on the jars quickly while the jam is still hot, or re-use a screw topped jar.