Easy one-pot chicken casserole

Name: Easy one-pot chicken casserole
Prep time: 5 min
Cook time: 50 min
Total time: 55 min
Cuisine: French
Ingredients: 8 bone-in chicken thighs skin pulled off and discarded; 1 tbsp oil; 5 spring onions sliced; 2 tbsp plain flour; 2 chicken stock cubes; 2 large carrots cut into batons (no need to peel); 400g new potato halved if large; 200g frozen peas; 1 tbsp grainy mustard; small handful fresh soft herbs, like parsley, chives, dill or tarragon chopped