1 bulb garlic, cut in half horizontally
1 large white onion, finely sliced
1.5kg/3lb 5oz medium sized, red-skinned potatoes, such as DΓ©sirΓ©e
100g/3Β½oz mixed salad leaves
1 tsp fresh thyme leaves
1 tsp Dijon mustard
salt and freshly ground black pepper
2 tbsp vegetable oil
1Β½ tbsp white wine vinegar
75g/3oz butter, plus extra to serve
1 x 250g/9oz whole petit Reblochon cheese, rind removed
1 free-range egg yolk
10 thick slices smoked dry-cured streaky bacon