Chinese pork with plums

Ingredients

• 2 tbsp vegetable oil
• 4 lean pork loin steaks
• 800 g plums (halved, stoned and coarsely chopped)
• 4 scallions (cut into 2 cm lengths)
• 4 orange sweet potatoes (peeled and cut into 1 cm cubes)
• 1 230g can water chestnuts (drained and rinsed, then sliced)
• 3cm piece fresh ginger (peeled and grated)
• 2 garlic cloves (crushed)
• 1 red chili pepper (deseeded and finely chopped (optional))
• 2 tsp sugar
• 1 tbsp salt-reduced soy sauce
• 1 tbsp cider vinegar
• 2 tbsp Chinese rice wine or dry sherry
• 1/4 tsp five-spice powder
• 2 tbsp cilantro (chopped)