Beef stroganoff

Ingredients (serves 4): Olive oil cooking spray 500g beef (fillet, sirloin or rump) trimmed, cut into thin strips 1 brown onion, thinly sliced 2 garlic cloves, crushed 250g button mushrooms, sliced 1 teaspoon paprika (smoked or plain) 3 teaspoons corn flour ½ cup salt-reduced chicken stock 1 tablespoon Worcestershire sauce ¾ cup Greek-style yoghurt ¼…