Add a teaspoon of baking soda to water. Wash the oranges with the skin in baking soda water. Pat dry with a clean kitchen towel.
Cut the oranges in half. Using a sharp fruit knife remove seeds from oranges.
Using a citrus juicer squeeze out the juice from the oranges. Scoop out the pulp in a separate bowl. Discard white pith, seeds, or transparent skin covering the pulp. Combine juice and pulp. Total they should be 500 gram (300 ml Juice + 200 gram Pulp).
Using a spoon remove the white pith inside the rind. It tastes bitter and spoils the marmalade. Now, julienne the orange rind or cut it into thin strips. It should be 60 gram. I use the rind of two oranges.
Add sugar, line juice, and mix. Cover and keep aside. After 15 minutes, sugar will be completely dissolved with the fruit. Do not rush this process.
Start cooking the marmalade in a heavy-duty ceramic, enamel, steel, or glass saucepan.
Stage 1, the marmalade will be watery, and white foam on top. Keep cooking on low heat, while stirring at regular intervals.
Slowly, the white foam will start reducing, the texture of the marmalade would thicken a bit. Use a potato masher or a ladle to gently mash the pulp and orange rind.
After 20 minutes on low heat, the white foam on top will disappear, pulp mashed nicely, and the marmalade will start sticking to the spoon. Turn off the heat.
Take a big spoonful of marmalade and spread it on a plate. It should be sticky and not watery with a sheen to it. That is the signal that marmalade is ready!
Allow the marmalade to cool down completely at room temperature. Store the cooled marmalade in a clean, sterilised glass jar with a tight-fitting lid.