This recipe was first inspired by the gorgeous blood oranges that have been at the market recently. They always remind of Italy and the time I spent there in college, so I made a Blood Orange Cardamom Marmalade and turned it into a Blood Orange Cardamom Crostata, a rustic Italian jam tart with gorgeous pieces of candied peel. The marmalade recipe is adapted from Elise Bauer's at Simply Recipes Sevilla Orange Marmalade —piccantedolce
Scrub the oranges and lemons with soap and water to make sure the skins are clean. Half all of the oranges and juice each half well until you have 2 cups of blood orange juice. Be sure to reserve any seeds or membranes in a separate bowl.
Take the rind from one of the juices halves, cut it in half and using a spoon or the edge of a small knife scrape out as much of the white pith as possible. The pith is what determine how bitter the end result will be. Repeat with each half and then thinly slice the rind into long strips until you have 3 1/2 cups of peel.
Half and juice each lemon and add the lemon juice to the orange juice, also reserving any seeds and membrane.
Put the seed and membranes into 4 layers of cheesecloth and tie up tightly with string.
Place the thinly sliced rind and water in a 4-5 quart thick-bottomed pot. Stir to combine. Place the cheesecloth with the seeds etc in the pot, it's smart to tie one end on to the pot's handle.
Bring the mixture to a boil and let boil uncovered for 20-30 minutes until the peels are soft. Taste the peel to determine softness. Remove from heat and place the pectin bag in a bowl and reserve until cool.
Once the pectin bag is cool enough to handle, squeeze it to extract any residual pectin into a bowl. Add any reserved pectin, the orange & lemon juices and the sugar to the juice/peel mixture. Place the cardamom seeds in a few layers of cheesecloth and into the pot.
Return to heat and bring to a boil over medium high heat, stirring occasionally for approximately 30 minutes. Cook until the temperature reaches 220F on a candy thermometer, being careful not to over cook. To test for doneness. Place a few small plates in the freezer and as the temperature gets close, place a tsp of jam onto the plate, place the plate back in the freezer for 30 secs to a minute, if it sets up without running all over it's done.
Remove cardamom pods. Ladle marmalade in sterilized jars (I place mine in a 200F oven for 10 minutes to sterilize) and boil in a hot water canner for 5 minutes. Keeps for a year properly canned or keeps in the fridge for 1 month. You can reserve 2 cups for the crostata if making in the next few days.