Mandolin (not necessary)
1. Wash and dry lemon and slice thin using a mandolin or a knife. Add to the bottom of the pot and cover with half the sugar. Add medium heat until sugar crystals dissolves, bring to simmer until the lemons are almost translucent.
2 Let's talk sugar. I start with a 4 to 1, fruit to white sugar ratio. This is a good jumping off point. I, personally, like the that sweet yet tart flavor of the fruit to shine. I've seen jams with as mush as a 1 to 1 ratio but find them way too sweet.
So, once your lemons are ready, add berries and the rest of the sugar to mixture. Stir until the sugar has dissolved and then crush berries with potato masher, stir completely. Slowly bring to boil over a medium high heat, stirring frequently. Cook for about 15 minutes or so. Be sure not to get it too hot and scorch your jam.
3. Once its done, add to ball jar and let it cool before putting into the refrigerator. You can keep your jam for up to a month. And of course you can can it at this time, but that's a whole 'nother blog!