Homemade Gnocchi with Mozzarella, pickled walnuts and lemon dressing

500g floury potatoes

125g type 00 flour

4 buffalo Mozzarella balls

2 tbsp grated pecorino

2 pickled walnuts, sliced

For the green herb and lemon dressing:

2 tbsp parsley

2 tbsp chervil

1 tbsp French tarragon

1 tsp marjoram leaves

juice 1 lemon

1 tbsp capers

3 tbsp rapeseed oil

salt

pepper