Strawberry-Rhubarb Jam with Basil

1 . Stage

Inspect four 4-ounce jars for cracks and rings for rust, discarding any defective ones. Immerse in simmering water until jam is ready. Wash new, unused lids and rings in warm soapy water.

2 . Stage

Place strawberries in a large bowl and crush with a potato masher. Transfer to a 4-cup liquid measure and add enough rhubarb to reach the 4-cup mark.

3 . Stage

Pour fruit mixture into a large, heavy pot and sprinkle citric acid over top. Stir sugar and butter into the fruit mixture. Bring to a rolling boil, stirring constantly. Mix in pectin and return to a boil. Cook for 1 to 2 more minutes, then turn off heat and skim off any foam. Quickly mix in chopped basil until fully incorporated.

4 . Stage

Ladle jam into hot, sterilized jars, filling to within 1/4 inch of the top. Run a clean knife or thin spatula around the insides of the jars to remove any air bubbles. Wipe rims with a moist paper towel to remove any residue. Top with lids and screw rings on tightly.

5 . Stage

Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars 2 inches apart into the boiling water using a holder. Pour in more boiling water to cover jars by at least 1 inch. Bring to a rolling boil, cover, and process for 10 minutes.

6 . Stage

Remove the jars from the stockpot and let sit 8 hours to overnight to completely seal; you should hear popping sounds as each jar seals. When completely cool, the middle of each lid should be sunken inward and should not spring back when touched.