Modernly, a marmalade means a preserve with shreds of peel. This is not the meaning in the renaissance. Then, it meant a sweet congealed paste of fruit and sugar. Since it is cooked as whole fruit and strained, there is no peel in the result.
The original recipe was: TAke ten lemmons or orenges & boyle them with half a dozē pippins, & ſo draw them through a ſtrainer, then take ſo much ſugar as the pulp doth wey, & boyle it as you doe Marmalade of Quinces, and then box it vp.
Since the recipe calls for either oranges or lemons, I wanted to try lemons this time. Also, I used Granny Smiths last time, and they never disintegrated. This time I used Red Delicious, which fall apart more easily. The lemons I found were a little small, I felt, so I used twelve instead of ten.
For good food safety, I canned using modern water processing technique with modern jars and seals.
Because it is cooked with the lemon pith intact, it retains a fair amount of bitterness, but not in an unpleasant way. There is definitely a lot of pectin, it set up solid easily.
Since it calls for even weights of pulp and sugar, I can't tell you exactly how much sugar. Expect around 45 ounces. My first batch weighed in at 43 oz., my second at 49.85 oz.
Hugh Plat's Apple Lemon Marmalade
12 medium lemons
6 large red delicious apples
sugar to match weight of pulp
1 tsp. salt
Cut lemons and apples in eighths. Put in a covered pot over medium low heat. Simmer until apples disintegrate.
Press through a colander. Weigh resulting pulp. Combine with equal weight of sugar, and return to stove over low heat. Add salt, simmer and reduce. Marmalade will darken.
Press through a strainer. Return to the stove on low heat to stay hot while canning, Can using water process or pressure canner.