Pulse strawberries and figs in a food processor. Continue to pulse until fruit reaches your desire consistency – I like my jam a little on the chunky side.
Place sliced strawberries and figs in a 6- or 8-quart saucepan.
Stir in lemon juice, then gradually add pectin.
Bring mixture to a full rolling boil over high heat, stirring constantly.
Add the sugar and stir to dissolve.
Place the butter on top of the preserves.
Return mixture to a boil. Continue to boil for one minute, stirring constantly. Remove pan from heat. Skim foam if desired.
The jam will continue to thicken as it cools. However, if you would like a thicker jam, add additional pectin and bring the jam to a full rolling boil again. Boil hard for one minute.
At this point you can process the jar using a water bath canning method, or you can store your jam in the fridge.