Hungarian Vegetable Marrow Stew with Dill (Tökfőzelék)

Ingredients

• 600 g vegetable marrow or zucchini (grated)
• 1 small onion (chopped)
• 2 tbsp oil or butter
• 1 tbsp flour
• 1 tsp Hungarian paprika
• 1 tbsp fresh dill (or 1 tsp dried)
• 1 tsp salt
• ½ tsp black pepper
• 1 tbsp vinegar or lemon juice
• 1 tsp sugar
• 200 ml sour cream
• 200–300 ml water or broth