Yes, I know it's bitter sweet but true marmalade is. That's what makes it so wonderful! If all you've ever had was Smucker's, you're in for a treat. It really is as easy to make as it looks. Makes wonderful stocking stuffers or hostess gifts during the holidays.
Wash oranges and lemon thoroughly. Cut oranges and lemons into 1/8" slices. Cut each slice into quarters. Place sliced fruit and their juices into a large stainless steel pot. Add water and bring to a boil, stirring often. Remove from heat and stir in sugar until it dissolves. Cover and allow to stand overnight at room temperature.
The next day, bring mixture to a boil. Reduce heat to low and simmer uncovered for 1.25 hours, stirring occasionally. In the meantime, wash canning bottles, lids and rings in hot soapy water and rinse well. Boil jars for 10 minutes. Then remove the pan from the heat and toss in the lids and rings and let set for at least another 10 minutes. Leave pieces in water until ready to fill.
After marmalade has cooked for 1.25 hours, turn heat up to medium and boil gently, stirring often for another 30 minutes or until it reaches 220 deg F. Place a small amount on a plate that has been refrigerated. Wait 30 seconds and then tilt plate. If it's still runny, cook a little longer.
Pour the marmalade into clean, hot Mason jars; wipe the rims thoroughly with a clean damp paper towel, and seal with the lids. Place in water bath canner with water that has come to a boil (with at least 1" over lids) and boil for 10 minutes. Remove to a cloth covered counter and let sit for 24 hours. Lids should pop. Store in the pantry for up to a year. Once opened, refrigerate for up to 3 weeks.
CAUTION: During the final 'boil', marmalade will get very hot and may splatter when you stir it. I find that stirring constantly helps and wearing long sleeves. If, during any stage, the marmalade begins to foam too much, just add 1/2 tsp of butter.
This recipe can be doubled (as it is only a half batch), but cooking time may need to be a tad longer.