Hi Captain I used the C.J.J. Berry's recipe with a few adjustments.......
5lb of ripe marrow flesh
2lb 6oz of sugar(to bring it up to 1.100)
4tsps citric acid
2 oranges
root ginger(I used 2ozs / gallon, depends on how gingery you like it)
1 gall. of water
pectic enzyme
yeast(Youngs wine yeast)
( You might need nutrient if you use a different yeast)
I cubed the marrow into half inch cubes,(happy chopping) I put the seeds in too,grated the ginger and sliced the orange put it all in a bucket with the acid then covered with boiling water, when cool enough add the pectic enzyme and a tsp. of yeast- stir twice a day for 5 days. Strain into a D.J. add water and the sugar, keep checking the gravity as you do this, I added a half tsp. of yeast to start it off again.
Hope that helps