Use a mortar and pestle or a spice grinder to crush the mustard seeds into fine dust.

Wash the strawberries, pat them dry. Hull the strawberries and cut each of them into small pieces.

Place them in a saucepan, toss with the sugar, and cook, stirring frequently using a wooden spoon to further break down the strawberry pieces by gently crushing them against the side of the pan.

Bring to a boil, reduce heat and let simmer for 10 minutes.

Remove from heat, let cool for 10 minutes then add the mixture to a food processor or blender and puree.

Add the ground mustard seeds to the mixture and blend thoroughly. Add the white wine and blend again.

Scrape the mixture into a bowl, stir in the vinegar.

Cover the bowl tightly with plastic wrap and let stand overnight at room temperature.

Transfer to a large 2 cup capacity or two 1 cup capacity sterilized jars.

Seal and let stand in a cool dark place for at least 2 weeks before using.