The horseradish adds an extra fieriness to the mustard.

Ingredients

3 Tablespoon Mustard seeds
250 ml Boiling water (8 fl oz)
115 Gram Mustard powder (4 oz)
115 Gram Granulated sugar (4 oz)
120 ml White wine vinegar, or cider vinegar (4 fl oz)
4 Tablespoon Olive oil
1 Teaspoon Lemon juice
2 Tablespoon Horseradish sauce

Method

Makes 400g (14 oz)
Place the mustard seeds in a heatproof bowl, pour the boiling water over and leave for 1 hour.
Drain, then tip into a blender.
Add the remaining ingredients and blend the mixture to a smooth paste.
Spoon it into sterilised jars. Store in the fridge and use within 3 months.