Beef Stroganoff

Name: Beef Stroganoff
Prep time: 25 min
Cook time: 1 h
Total time: 1 h 25 min
Cuisine: European, Eastern European
Ingredients: 40 g olive oil; 600 g beef fillet steak, cut into strips (1 cm x 4 cm); 2 pinch ground black pepper; 1 tsp salt; 100 g brown onion, cut into pieces; 1 garlic clove; 250 g fresh mushrooms, cut into quarters; 30 g water; 10 g gluten free cornflour; ½ tsp Meat stock paste (see Tips); 1 tsp English mustard or other strong mustard e.g. Dijon; 200 g cream; 50 g pickled gherkins, cut into strips (optional); fresh flat-leaf parsley, leaves only, for garnishing