Prepare a small saucepan with lids for jars. Get lid rings out and ensure you have one for each lid. Bring lids to a simmer, and then turn down heat but keep warm. Sterilize jars, ladle and jam stirring spatula in the dishwasher or boil in hot water for 15 minutes. Use the same large pot that you will process the jam in. Remove jars, ladle and spatula, and set on a clean towel near where you will be cooking the jam. If you have sterilized jars and tools in dishwater, prepare a hot water bath in a large stock pot or canning pot. I fill ½ full, then fill to the necessary fill line after jam jars are added in step 8.

To a large heavy bottomed pan, add sliced oranges, sliced lemon peel and lemon juice. Add 750g water. Bring to a boil, cover pan slightly, turn down heat to a strong simmer and cook for 40 minutes. The oranges will be tender.

To the orange-water-lemon mixture, add the sugar.

Put a plate in the freezer.

Bring the jam to a good simmer over medium-high heat. Cook jam until it thickens and darkens slightly in color. Stir occasionally, to prevent scorching. It will take about 15-25 minutes for the jam to reach 221-222F, but it must be cooked to this temp for texture, so have patience.

You can test your jam texture as it cooks by putting a small blob on the cold plate, but this is purely optional if you cook to temperature. I still do it, for fun!

Once temperature is reached, off the heat and set the pan on a heat-proof surface or trivet. Ladle the jam into the sterile jars to just below where the threads begin (the jam will expand a bit during processing). Wipe down the jar of any jam that spilled onto the rim. Place a warm lid on each jar, followed by a band. Tighten bands hand-tight.

Process the jam: place a kitchen towel or a canning trivet into the hot water bath from step 1. Add jam filled jars. Add water to cover the jam fill line in jars by 1”. Bring to a full boil. Boil pints and half pints for 10 full minutes. Remove jars of jam to a clean towel, and allow to cool completely and set - 24 to 48 hours. Test for seal (push down on lid, should have been sucked into the jar; if not, re-process in boiling water for 10 minutes or store jam in the fridge and consume within a few months). For properly processed jam, store in a dark, cool place for up to 1 year. Refrigerate after opening.