If you don't want to use liquid pectin then use the Strawberry Jam recipe and substitute rhubarb for 1/3 of the strawberries.

Yes you can use frozen rhubarb but thaw and drain it first.

Dave

1 large lemon
2 pounds of strawberries, hulled
3/4 pound of rhubarb, cut into app. 3/8-inch cubes
4 1/4C sugar

1. Squeeze the juice from the lemon. Put the seeds into a spice bag, and put the bag and juice into a preserving pan. Add the strawberries and slice or mash them if they are large and firm. Add the rhubarb. Over low heat, simmer the contents until the rhubarb is tender, about 30 minutes.

(Thawed and drained may take less - frozen and not drained may take more)

2. Remove the pan from the heat and add the sugar. Stir over medium heat until sugar is dissolved. Raise the heat to medium-high and boil the jam, stirring and skimming off the foam, until a drop mounds in a chilled dish.

3. Ladle the jam into pint or half-pint mason jars. Add lids and rings, and process the jars for 10 minutes in a boiling-water bath.

Small Batch (by Ellie Topp) has a rhubarb variation of Favorite Strawberry Jam, strawberry version yields 2.5 C, rhubarb version yields 3C:

4C halved or quartered firm strawberries

(for rhubarb version *add* 1C finely chopped rhubarb)

2C sugar
1/4C lemon juice

1. Mix berries (and rhubarb) with sugar and let stand for 8 hours, stirring occasionally.

2. Place mixture in medium stainless saucepan. Bring to a boil over medium heat. Add lemon juice, return to boil, and boil rapidly for 5 minutes. Remove from heat, cover and let stand 24 hours.

3. Bring mixture to a full boil over high heat and boil rapidly for 5 minutes, stirring constantly. Remove from heat.

4. Ladle into hot jars and process for 10 minutes.

HTH