Heat your oven to 200°C/Fan 180°C/Gas 6. Scatter the sun dried tomatoes into a heatproof bowl or jug and pour over 300ml boiling water. Set aside to soak for 15 mins.
Cut the broccoli into small florets (you can use the stalk in stir-fries, so don’t chuck it away). Slice the cherry tomatoes in half. Cut the lettuce lengthways into quarters. Thinly slice the chilli on an angle. Peel and thinly slice the garlic. Arrange the broccoli, tomatoes and lettuce in a large roasting tin. Scatter over the chilli (use fewer slices for less heat) and garlic with a pinch of salt and pepper. Drizzle over 1 tbsp oil. Toss till evenly coated. Slide the tin into the oven and roast for 10-12 mins, till the broccoli is tender.
Meanwhile, pour the buckwheat into a small pan and sprinkle in a pinch of salt. Cover with 150ml boiling water. Return to the boil, then reduce to a simmer and cook for 8-10 mins, till the grains are tender with a slight bite. Drain through a sieve and rinse with cold water to cool slightly.
Pour 1 tbsp aged balsamic vinegar into a small bowl. Whisk with 1 tbsp oil and a pinch of salt and pepper. This is your dressing.
The sun dried tomatoes should be softened by now. Drain them, then roughly chop into pieces.
Tip the roast veg into a large bowl. Add the buckwheat and sun dried tomatoes. Pour over the dressing and toss to mix. Taste and season, then spoon onto a couple of plates and serve.