Step 1 Preheat oven to 180ºC. Cut each chicken breast horizontally to give 4 thin fillets. Place each piece of chicken between 2 pieces of baking paper and pound until an even thickness.
Step 2 Place chicken onto a clean work surface, top each with 1/4 of the spinach leaves. Sprinkle with grated cheese, then place 1/4 of the tomato into the middle of each. Roll each firmly, starting at short end, to enclose filling. Secure with toothpicks.
Step 3 Spray a large non-stick frying pan with oil and place over high heat. Cook chicken, for 1 minute each side, or until golden. Transfer to a baking tray and bake for a further 15-20 minutes, or until cooked through.
Step 4 Meanwhile, cook sweet potato in a saucepan of boiling water for 5-6 minutes until tender. Drain, return to saucepan and mash until smooth. Stir through chives. Thickly slice chicken, then serve with mash, steamed broccolini and green beans.