Overview: Test cook Lan Lam makes host Julia Collin Davison Roast Chicken with Couscous, Roasted Red Peppers, and Basil. Tasting expert Jack Bishop talks all about grains, and science expert Dan Souza reveals the magical potential of chocolate. Test cook Erin McMurrer bakes host Bridget Lancaster a showstopping Rhubarb Upside-Down Cake.