Core and dice the pears and place in a large bowl.
Add the sugar and lemon juice and stir so that the diced pears are covered in sugar.
cover the mixture with a towel and let sit for 8 hours, or overnight.
Transfer mixture, including all the sugar and lemon juice, to a large pot.
Add the liquid pectin in and bring the mixture to a boil over medium heat. Stir frequently to prevent fruit from sticking to the pan.
Let the mixture simmer for ten minutes or so. Once the fruit is becoming nice and soft, use an immersion blender and puree until very smooth.
Continue cooking until the jam for another 20 minutes or until it reaches your preferred level of consistency, stirring occasionally.
Once the mixture has reached its desired consistency, remove from the heat and pass the jam through a fine mesh sieve. Discard any solids.
Transfer the jam to a heat proof storage container and let cool completely before placing in the refrigerator. Jam will keep in the fridge for up to a month