Heat your oven to 220°C/Fan 200°C/Gas 7. Put a baking tray on the top shelf to heat up. Cut the peppers into 1-2cm slices, discarding the seeds and white bits. Toss with 1 tbsp oil and a little salt and pepper. Tumble onto the warm tray. Roast for 10-15 mins or till a little charred around the edges.
Tip the bulgar wheat into a heatproof bowl and stir in a pinch of salt. Pour over 300ml boiling water and cover the bowl with cling film or a large plate. Set aside for 15 mins.
Zest the lemon into a bowl. Roughly chop the basil leaves and add to the bowl with the zest, along with the yogurt and a pinch of salt and pepper. Stir well to combine.
Squeeze the lemon juice into a separate bowl. Peel and grate in the garlic. Stir in 1 tbsp olive oil. When the bulgar is cooked, stir the dressing into it along with the spinach leaves and the cooked peppers.
Pile the salad onto plates and serve with generous dollops of the basil yogurt.