Wash the oranges well and dry with a clean cloth or paper towel.
Remove colored zest (just the colored part, not the white pith) from 6 of the oranges using a small zester (this one works so well). If you can’t get one of the small zesters, use a vegetable peeler to remove just the colored zest. Then cut the peel into thin slivers, or finely chop.
Trim off the top and bottom of each of the zested oranges. Then, cut off all of the remaining white pith. Cut each orange in half and remove the center white core. Coarsely chop the remaining fruit, reserving any juice and discarding any seeds.
Measure exactly 2⅓ cups of the fruit mixture into large bowl. If you dont have enough, zest and peel more oranges until you have exactly 2⅓ cups. Stir in sugar until well mixed (the mixture will be grainy at this point).
(As an alternative to using the microwave, you can combine the zest, chopped oranges, juice and sugar in a large pot. Bring the mixture to a full rolling boil and boil for 30 seconds then remove from the heat and proceed as directed below with the pectin.)
Mix water and pectin in a medium saucepan. Bring to a full rolling boil on high heat, stirring constantly. Boil and stir for 1 full minute.
Add hot pectin and lemon juice to the fruit mixture and stir for 3 minutes. (Don't cheat! Set a timer.) The sugar should be dissolved and the marmalade should no longer be grainy. (A few sugar crystals may remain.)
Fill prepared containers immediately to within ½-inch of tops. Wipe off top edges of containers and immediately cover with lids. Let stand at room temperature 24 hours (if you can wait!). Marmalade is now ready to use. Store in refrigerator up to 3 weeks or freeze extra containers up to 1 year. Thaw in refrigerator before using.
See Café Tips above in the post for more detailed instructions and tips.
This recipe yields 5 cups of jam. The number of jars will depend on the size of your jars.