(Adapted from www.davidlebovitz.com)
Below is a recipe I found that will put your rhubarb to excellent use. You can use any type of berry (raspberries, blackberries, etc). I used strawberries because their sweetness balance the tart flavor of rhubarb. I also cut the recipe in half since I plan to eat it in a few months and avoid having to process the jars. If you are going to store for longer you will have to process (sterilize) the jars.
Here is a link to the recipe and tips on canning:
3 pounds (1.25kg) rhubarb, trimmed and sliced into 1/2-inch (2cm) pieces
2 cups (250g) packed mixed berries, fresh or frozen
1 cup (250ml) water or apple juice
5 1/2 cups (1kg, plus 100g) sugar
juice of one lemon
pinch of salt
optional: 1 tablespoon kirsch
1. In a large pot, mix the rhubarb, berries, and the water or apple juice. Cook, covered, stirring frequently over moderate heat, until the rhubarb is cooked through and thoroughly tender. It should take about 15 minutes.
Put a small plate in the freezer.
2. Add the sugar, lemon juice, and salt, and cook, uncovered, skimming off and discarding any foam that rises to the surface, until the jam is thick and passes the wrinkle test.
To do so, place a small spoonful of the jam on the frozen plate. Return it to the freezer and check it a few minutes later; if the jam wrinkles when nudged, it’s done. You can also use a candy thermometer; jam jells at approximately 220F (104C).
3. Stir in the kirsch, if using, then ladle the jam into clean jars, cover, and store in the refrigerator.
Makes 5 one cup (250ml) jars