Place the chopped pears and lemon juice into a large, microwave-safe bowl.
Cover loosely with a plate or microwave-safe lid.
Microwave on full power (based on 800W) for 10 minutes, stopping to stir after 5 minutes.
Carefully remove the bowl from the microwave.
Add the sugar and use a hand blender to pulse the mixture a few times. Aim for a chunky texture rather than a perfect purée.
Return the bowl to the microwave, uncovered, and cook for a final 15–20 minutes.
Stir every 5 minutes to prevent sticking.
The jam is ready when most of the water has evaporated. Test the set by placing a small spoonful onto a chilled plate; if it holds its shape and wrinkles when pushed, it's done.
Allow the jam to cool completely before potting into sterilised jars. It will keep for up to a month in the fridge.
Keep a small plate in the freezer to test for set. A dollop of ready jam will wrinkle when pushed.
