Step 1 Bring a large saucepan of water to the boil. Add sweet potato and cook for 5–6 minutes, or until just tender, adding broccoli florets for last 2–3 minutes. Drain cooked vegetables and set aside.
Step 2 Meanwhile, preheat grill. Heat olive oil in a medium non-stick, ovenproof frying pan set over medium heat. Add onion; cook for 1–2 minutes, or until soft.
Step 3 Remove frying pan from heat. Arrange reserved sweet potato and broccoli florets evenly over onion mixture in pan.
Step 4 Whisk eggs, milk and ricotta in a large jug. Pour egg mixture over vegetables, tilting frying pan to evenly distribute mixture. Top mixture in pan with half of the cherry-tomato halves, cut-side up.
Step 5 Place frying pan under medium grill and cook for 5–6 minutes, or until frittata is almost set (cooking time will depend on size of pan). Remove pan and sprinkle frittata with grated parmesan. Return pan to grill for 3–4 minutes, or until frittata turns golden.
Step 6 Toss remaining tomato halves with salad leaves in a large bowl. Serve frittata wedges with salad.