- Wash lemons and gently cut out "buttons" at the top of the lemon (part where the stem would be). Peel the lemon peel from the lemon. It’s OK and even a good thing to get a just bit of the white pith. Slice the lemon peel into strips 1/4" or thinner. Place the peel into a large non-aluminum bowl or pot.
- Cut the peeled lemon in half and juice. Pour the juice into the bowl with the lemon peel. Remove any seeds (pips) that fall into the juice and set them aside. Set aside the lemon halves - you need them for the next step.
- Cut the leftover lemon halves into medium-sized chunks. Include the leftover seeds and any fruit left from juicing. Put this in a piece of cheesecloth or thin muslin, tie up into a bag, and place in the bowl. (Any fabric too thick and the pectin won't drip through properly.) The bag ingredients contribute the natural pectin to the marmalade and cause it to gel.
- Pour 1.75 liters of water into the bowl, cover, and let sit overnight at room temperature.
- The following day: Pour the whole mixture into a large cooking pot. Slowly bring the ingredients to a boil, then reduce heat and simmer for about 1 & ½ hours to 2 hours.
- Remove the cheesecloth with the lemon fruit, seeds, etc. Set it on a plate to cool for about 10 minutes or so.
- While the bag is cooling, prepare your canning jars in a large water bath of boiling water.
- Now squeeze the bag into the pot. A lot of gluey looking stuff will seep out. You want this! It is the natural pectin from the lemon, which will make the marmalade nice and thick, but will retain some bitterness. Squeeze out as much as you can to make a thick marmalade. To make a clear, but not so thick marmalade, don't squeeze so much.
- Toss the bag contents into your compost.
- Put 2 or 3 small saucers in the refrigerator or freezer for testing your marmalade set point.
- Add sugar and lavender flowers to the pot and stir over low heat until sugar is dissolved. Raise heat and bring to a rolling boil. Then boil rapidly until you reach the setting point - the point where the marmalade begins to "gel." Test every 10 minutes for set. Stir fairly often to prevent sticking. It can sometimes take anywhere from 20 to 45 minutes for the marmalade to set. It's not an exact science!
- To test: Take a saucer from the fridge and drop a spoonful of the marmalade onto the saucer. Set aside for about a minute, and then tilt the saucer. If the mixture flows freely, it is NOT ready. It should move VERY slowly, like honey. Another way is to press your finger into the dab or marmalade and see if it “wrinkles.” If so, it’s ready.
- When set, remove the marmalade from the heat and cool for about 10 minutes. This prevents the peel from rising to the top of the jars.
- While the marmalade is cooking, boil 4 Mason jars, the screw tops (not the flat lids), tongs, and your ladle in rapidly boiling water for 10 minutes to sterilize. DON'T let jars touch the bottom of the pot - use racks to elevate them. After you turn off the heat, throw in the flat lids.
- Ladle marmalade within 1/2 inch or 3mm from the screw top of sterilized jars. Be careful - it's hot stuff! Wipe the outer rim with a wet paper towel, then seal immediately. Don't over-tighten the jar rings.
- Put filled jars back into the hot water bath, return to boiling, and boil for 10 to 15 minutes. Be careful not to let the jars touch each other. Remove carefully with tongs and set to cool at room temperature.
- You should hear the jar tops “pop” within an hour or two after canning. This means they have sealed. If they do not seal properly – ugh. Go to the Internet and find out how to reprocess. (I’m willing to bet you will not have to do this. Always use new jar lids when canning!)