finely grated rind and juice of 2 oranges
1 cup mustard seed (yellow is called for, but you could mix brown)
1/3 cup white wine (or I've used apple cider) vinegar
2 teaspoons salt
1 teaspoon dried tarragon (or 1 tablespoon chopped fresh tarragon)
Combine the rind and orange juice in a small pan and bring to a boil; remove from heat and cool.
Coarsely grind aboud 3/4 of the mustard seed. Place in a glass bowl with remaining whole mustard seed. Add the boiled orange juice and rind. Mix well and let it sit for about 5 minutes. Then stir in the vinegar, salt and tarragon.
Pack the mustard into sterilized jars and process about 10 minutes. The mustard is ready to eat in a few days. This recipe is supposed to yield about 2 pints, but it varies (today it was 1.75 pints).