Bluebarb jam

During the recent rhubarb taste-testing, the consensus was that the best treat of all was the "bluebarb" jam. (Much easier to say than "blueberry rhubarb.")

The recipe is from a wonderful little book by Madelaine Bullwinkel, called Gourmet Preserves Chez Madelaine. I particularly like the way she relies on natural pectin, rather than the commercial variety.

Here's the gist of how to make your own bluebarb jam (but do check out the Bullwinkel book for more information):
Simmer, uncovered, on medium-low heat for about twenty minutes: 1/4 cup of water, a pound of blueberries (about a pint) and a pound of rhubarb chopped into 1/2" pieces.
Add 2 1/2 cups sugar, half a cup at a time, stirring well, and bringing the mixture to a simmer between each addition. Add 1/2 tablespoon of lemon juice and the zest of the lemon.
Simmer for another fifteen minutes, raising the heat to medium. Toward the end, it will splatter, and may be covered between stirrings. Makes 4 1/2 cups. After it's cool, keep it refrigerated unless you process it according to standard canning procedures.

I'm not particularly finicky about the gelling -- if the result is thick, I call it jam; if it's runny, I call it ice cream topping -- but for those who are so inclined, the jam should gel when it reaches 212 degrees Fahrenheit. You can also test more informally by putting a little bit on a plate and putting the plate in the freezer for a minute or two, and seeing if it gelled, which also gives you an excuse to taste-test it.