Chicken with Pepper and Asparagus

Ingredients

• 2 tsp olive oil
• 1 yellow pepper (cut into 1 cm wide strips)
• 3 garlic cloves (finely chopped)
• 3 green onions (cut into 2 cm lengths)
• 370 g chicken breasts (cut crosswise into 1 cm wide strips)
• 750 g asparagus (cut into 5 cm lengths)
• 1 1/2 tsp lemon rind (grated)
• 1/2 tsp fresh rosemary (chopped)
• 3/4 cup reduced-salt chicken stock
• 1 1/2 tsp cornstarch (blended with 1 tablespoon water)
• 2 tbsp walnuts (toasted, finely chopped)