Chop fresh rhubarb stalks into small pieces and combine with sugar, lemon juice, and cinnamon. Allow to sit for 10-15 minutes.

Heat over medium heat, stirring frequently until mixture is juicy and bubbly (5-7 minutes).

Stir in powdered pectin gradually and continue stirring for another 2-3 minutes until well integrated.

Bring the mixture to a vigorous boil and boil for 1 minute while stirring constantly.

Optional: Add vanilla for extra flavor, stir gently and turn off the heat.

Prepare sterilized canning jars while the jam cools slightly.

Fill each jar with hot jam, leaving 1/4 inch of headspace, and wipe rims clean.

Process jars in a water bath canner for 10 minutes to ensure sealing.

Check seals after 12-24 hours; store those sealed in a cool, dark place.