Ingredients:
- 2 lbs fresh strawberries, hulled and quartered
- 2 lbs fresh rhubarb, sliced into ½-inch pieces
- 2 tbsp fresh lemon juice
- 1 tbsp unsalted butter
- 5 cups granulated white sugar
- 1 box (57g) powdered fruit pectin
- 1/4 tsp salt
Instructions:
- Wash and dry the strawberries and rhubarb. Quarter the strawberries and chop the rhubarb into small, uniform pieces, then combine both in a large, heavy-bottomed stainless steel pot.
- Stir in the lemon juice, butter, and powdered fruit pectin.
- Heat the mixture over medium-high heat, stirring constantly to ensure the pectin is fully dissolved.
- Bring the mixture to a rolling boil (a boil that cannot be stirred down), then stir in the granulated sugar.
- Bring the jam back to a full bubbling boil for exactly one minute, or until the temperature reaches 220°F (104°C) on a candy thermometer.
- Ladle the hot jam into sterilized half-pint canning jars, leaving 1/4 inch of headspace.
- Wipe the rims clean, center the lids, screw the rings finger-tight, and process in a boiling water bath for 10 minutes.