Kid-friendly Japanese curry

Ingredients

• 60g unsalted butter
• 80g plain flour
• 2 tbsp mild curry powder
• 1 tbsp garam masala
• ​1½ litres lightly salted chicken stock
• 2 tbsp tomato sauce (ketchup)
• 1 tsp Worcestershire sauce
• 1 tbsp dark soy sauce
• 1 apple, peeled and grated
• 800g chicken thigh fillets, cut into 3cm pieces
• 1 large brown onion, thickly sliced
• 2 large carrots, peeled and cut into irregular chunks
• 2 sebago potatoes, peeled and cut into irregular chunks
• steamed rice, to serve
• green peas, to serve