1. Prep the Fruit:

• Wash and chop rhubarb and strawberries into small, even pieces.

• Combine them in a large, heavy-bottomed saucepan.

2. Add Sugar & Lemon:

• Add sugar, lemon juice, and lemon zest (if using) to the fruit.

• Stir to combine and let sit for 10–15 minutes to macerate and release juices.

3. Cook the Jam:

• Bring the mixture to a boil over medium-high heat, stirring often.

• Reduce heat to medium-low and simmer for 30–40 minutes, stirring occasionally, until thickened.

• Use a spoon or potato masher to gently break up the fruit as it softens.

4. Check for Doneness:

• To test, place a small amount on a cold plate. If it wrinkles when pushed, it’s ready.

• If not, cook a little longer, stirring often to prevent burning.

5. Cool & Store:

• Remove from heat and let cool slightly.

• Transfer to clean jars. Store in the refrigerator for up to 3 weeks, or water bath can for shelf-stable storage (10-minute process for 8 oz jars).