Roast chicken with Caesar vegetables

Celebrate asparagus season with this spring chicken recipe drizzled with a zingy Caesar dressing. Serve with new potatoes for a real family feast

6 anchovy fillets
2 tbsp red wine vinegar
2 tbsp Dijon mustard
2 garlic cloves
1 medium egg
150ml vegetable oil
15g Parmesan, finely grated
¼ small pack tarragon, 1 tbsp finely chopped, the rest snipped off the stem to make small sprigs
25g soft butter
4 anchovy fillets, finely chopped
1½ kg whole free-range chicken
200g fine-stemmed asparagus spears, ends snapped off if woody
200g green beans, trimmed, halved and blanched for 2 mins
170g frozen peas
¼ baguette, cut into chunky croutons

To make the dressing, put the anchovies in a small bowl, add the vinegar, mustard, garlic and egg, then blitz with a stick blender until well mixed. Gradually add the oil in a thin stream until it thickens into a creamy dressing. Stir in the Parmesan, season and chill until ready to serve.
For the chicken, heat oven to 190C/170C fan/gas 5. Beat 1 tbsp chopped tarragon with the butter and anchovies, then rub it under the breast skin of the chicken. Rub any remainder all over the bird and roast for 1 hr until the chicken is golden and nearly cooked. After 1 hr, add the asparagus and beans to the roasting tin around the chicken. Cook for 12 mins, then scatter the peas over and cook for another 3 mins until the chicken is cooked through, the vegetables are tender and the peas are hot.
Meanwhile, put the croutons on a baking sheet and toast in the oven for about 10 mins until golden and crisp.
Scatter the chicken and vegetables with the croutons and tarragon sprigs, and spoon over a little dressing. Serve the rest of the dressing separately.