In a large bowl, mash strawberries using a potato masher. Measure out exactly two cups, setting aside any extra mashed berries, and add the 2 cups back to bowl. Save the extra mashed berries for another use. You want to be as exact with the recipe measurements as possible.
To the 2 cups of mashed strawberries, stir in 4 cups of granulated sugar. Mix well to combine, making sure the sugar is completely incorporated, and then let the berry mixture stand for 10 minutes, stirring occasionally.
After 10 minutes, in a small saucepan, combine fruit pectin and 3/4 cup water. Bring to a boil on high heat, stirring constantly. When it boils, set a timer for one minute. Continue to stir constantly and then remove from heat when it has boiled for one minute.
Stir pectin and water mixture into the fruit and sugar mixture. Stir constantly for about 3-4 minutes or until sugar is completely dissolved and mixture is no longer grainy. Stir in chopped basil leaves.
Pour mixture into freezer containers with tight fitting lids (jars work great). You'll need five 8 oz. containers or something comparable. Total yield is 5 cups.
Let jam stand at room temperature for 8 hours before moving to the fridge or freezer. If you freeze it, thaw it in the fridge overnight before using.
This recipe makes 5 cups of jam. Nutrition information is based on serving size of 2 tablespoons.