Combine the raspberries and lemon juice in a small saucepan over medium heat. Stir and mash the fruit until it is completely or nearly-completely liquified.

Stir in the sugar and pectin and bring the mixture to a full boil over high heat (a full boil means the bubbles do not diminish when stirred.) Once the mixture is fully boiling, do not stir and set a timer for 1 minute. When the 1 minute is up, remove the jam from the heat.

Allow to cool slightly, about 3-5 minutes, and stir in the rosewater.