Step 1 Preheat oven to 200°C. Place tomatoes on a tray lined with baking paper and spray with oil. Roast for 15–20 minutes, until cooked. Keep warm.
Step 2 Meanwhile, steam potatoes until tender. Cool for 10 minutes.
Step 3 While potatoes cool, spray a large frying pan with oil and place over medium-high heat. Cook chicken until golden. Set aside and keep warm.
Step 4 Carefully peel and mash potatoes (they may still be hot). Stir in egg yolk and parmesan. Add flour until the mixture forms a slightly sticky dough (add a little more flour if necessary). Knead for 5 minutes, until a smooth dough forms.
Step 5 Divide dough into 4 portions. Roll out each portion onto a lightly floured surface to form a 2cm-thick sausage shape. Cut into 3cm-long slices and form each piece into an oblong shape.
Step 6 Cook gnocchi in a large saucepan of boiling water for 2 minutes, until they float to the surface. Drain and return gnocchi to pan. Add pesto to pan and toss gently. Stir through chicken and top with roasted tomatoes. Serve with salad.