Step by step

Method

4 steps

1. 1

   Crush berries in a wide pot with a potato masher, leaving some chunks. Stir in lemon juice.

2. 2

   Mix pectin with 1/4 cup of the sugar; stir into berries. Bring to a full rolling boil over high heat, stirring often.

3. 3

   Add remaining sugar and butter all at once. Return to a rolling boil that you cannot stir down; boil hard 1 minute, stirring constantly.

4. 4

   Remove from heat. Skim foam. Ladle into clean jars, leaving 1/4-inch headspace. Cool to room temp, then refrigerate. Jam thickens as it chills (check set after 24 hours).