Step 1 Cook pasta following packet directions until tender. Drain, reserving 1/4 cup cooking water.

Step 2 Meanwhile, place pesto, tomatoes and sour cream in a medium-sized saucepan. Heat over a low heat until warmed through and combined. Add reserved cooking liquid. Stir to combine.

Step 3 Add pasta to sauce and toss generously to coat. Dish out and top with rocket and lemon zest. Serve with a large green salad.