Wash and dry the fruit thoroughly and cut the strawberries in half (skip if using frozen berries).

In a medium sized saucepan (2 quarts or larger), add the berries, sugar, and 1/4 cup of the lemon juice.

Heat the ingredients over medium high heat until the juices have seeped out and the mixture starts simmering, about 3-5 minutes.

Continue to simmer the berries for about 15 minutes until the fruit softens. Using a spatula or wooden spoon, stir the mixture periodically.

Once the fruit has softened, use a potato masher or a fork to start mashing the berries. Mash until no whole fruit remains, but don't worry about getting everything perfectly smooth at this point.

Continue to simmer the jam over medium-high heat for another 35-45 minutes, stirring often to prevent scorching. Turn down the heat to medium if the mixture bubbles too furiously.

The jam is ready when the mixture looks like it's "breathing" and the bubbles are smaller and thickened.

The mixture should be as thick as loose pudding and a spoon should leave visible drag marks when moved through the jam. There should be no visible fruit juice, and the foam will have subsided. The mixture will have reduced to 2 1/2-2/34 cups as well.

Remove the jam from the heat and stir in 1 tablespoon of lemon juice. Allow the jam to cool at room temperature.

Once the jam has cooled, transfer to a clean jar or container, pop a lid on it, and store it in the fridge for up to a month or in the freezer for even longer!