Prepare the Olallieberries: Wash fresh Olallieberries or thaw frozen berries. Mash them with a potato masher or fork, leaving some chunks.
Cook the Berries: In a large saucepan, combine mashed berries and lemon juice. Heat over medium until berries release their juice.
Add Sugar and Pectin: Stir in sugar and pectin until dissolved. Bring the mixture to a boil and let it boil for 2-3 minutes.
Boil and Stir: Boil for about 10 minutes, stirring constantly. Check consistency by placing a small amount on a cold plate. If it wrinkles, it’s ready.
Jar the Jam: Pour the jam into sterilized jars, leaving 1/4 inch at the top. Seal and cool to room temperature.
Store or Serve: Refrigerate for up to 3 weeks, freeze for longer storage, or process in a water bath for long-term storage.