Peel and finely dice shallots, wash, core and finely chop the chilli pepper. Wash the rhubarb and cut into pieces.
Heat 2 tablespoons of oil in a saucepan and sauté shallots, chilli, rhubarb and mustard seeds. Stir in the honey. Deglaze everything with vinegar, bring to the boil and simmer uncovered over low heat for 30–35 minutes. Season to taste with salt, sugar and pepper.
Immediately fill the chutney to the brim in two screw-top jars (400 ml) that have been rinsed with hot water. Close, turn over and let stand on the lid for about 5 minutes.
The chutney can be kept in the refrigerator for about 3 weeks.