Rinse about 4 cups of fresh mulberries gently under cold water to remove dirt and stems. Drain and let them dry slightly.

In a large heavy-bottomed pot, add the mulberries, 1 ½ cups of sugar, and ¼ cup of water. Stir to combine and let it sit for 10–15 minutes to macerate the berries.

Place the pot over medium heat and bring to a gentle boil. Reduce heat slightly and simmer, stirring frequently, for about 20–25 minutes until the mixture thickens and deepens in color.

Stir in the fresh lemon juice, a pinch of sea salt, and vanilla if using. Continue to simmer for another 5 minutes.

Test the jam by placing a small spoonful on a chilled plate; if it wrinkles when pushed with your finger, it’s done.

Ladle the hot jam into sterilized glass jars, leaving about ¼ inch headspace. Seal tightly and let cool to room temperature before refrigerating.