Breton Braised Flageolets and Celery

This is a dead simple recipe passed to me by my Breton French teacher. Almost instant and full of flavour.
For four
- 3 sticks of celery, string removed
- Three fifths of a brick of butter/150g/5 oz butter
- 6 banana shallots, peeled and quartered
- 4 fat cloves of garlic, crushed with 1 tbsp smoked salt
- 160 ml/⅔ cup marsala
- 2 x 400g/14 oz tins of flageolet beans, drained
- 3 tbsp crème fraîche
- Indonesian long pepper
- Melt the butter gently in a medium-sized saucepan
- Meanwhile cut the celery across the stalk and add to the butter
- Add the shallots and the garlic
- Add the marsala, beans, and crème fraîche and bring to the boil
- Add the pepper