Roast Walnut and Squash Medley With Persillade

Name: Roast Walnut and Squash Medley With Persillade
Ingredients: 1 red onion, thickly sliced; 10 ½ oz. peeled winter squash, cut into 1 ½-inch cubes; 7 oz. chicory, roughly chopped (about 2 heads); 7 oz. portobello mushrooms, thickly sliced; 7 oz. red peppers, halved, deseeded, and roughly chopped; 2 oz. walnuts, halved; 2 oz. cooked chestnuts, halved; 2 Tbsp. olive oil; Sea salt and freshly ground black; Pepper; 4 Tbsp. extra-virgin olive oil; 1 oz. fresh flat-leaf parsley, leaves and stalks finely chopped; ½ oz. fresh tarragon leaves, finely chopped; ½ oz. fresh dill, finely chopped (chervil, fennel fronds, or chives will also work); ½ shallot, finely chopped; 1 garlic clove, finely chopped