Adjust rack to middle position and preheat oven to 450 degrees. Wash and dry produce. Gently separate agnolotti.

In oven-ready tray, combine cream sauce base, veggie stock concentrate, mushroom stock concentrate, garlic powder, salt, pepper, and as much tuffle zest as you like. (For 4 servings, evenly divide ingredients between two trays.) Add agnolotti (for 4, divide between two trays); stir until coated in sauce. Top with spinach (for 4, divide between two trays). TIP: Evenly spread out spinach and press down, making sure no leaves hang over the edges of your tray!

Cover agnolotti bake tightly with foil. Bake on middle rack until ravioli are al dente and spinach has wilted, 25-30 minutes. (For 4 servings, place both trays side-by-side on top rack.)

Carefully remove foil from agnolotti bake (watch out for steam!). Stir until everything is combined and evenly coated in sauce. Taste and season with salt and pepper if desired. Divide agnolotti bake between shallow bowls. Garnish with Parmesan and walnuts. Serve.