Wash and dry all produce. Preheat broiler to high or oven to 500 degrees. Halve, peel, and thinly slice onion. Strip thyme leaves off stems (you’ll want about 11/2 TBSP). Discard stems.

Heat 2 TBSP butter in a large ovenproof pan over medium heat. Add thyme and onions, and cook until softened, 5-6 minutes. Season with salt and pepper. Add stock concentrates and 21/2 cups water, and bring to a simmer.

Add ravioli to pan, cover, and cook 3-4 minutes. Uncover and increase heat to high. Spoon broth over ravioli until they're tender and broth is thickened and reduced, 5-6 minutes. If broth evaporates before ravioli are tender, add a splash of water. To keep ravioli from sticking, shake pan occasionally.

In a small bowl, combine panko, Parmesan cheese, a large drizzle of olive oil, and a pinch of salt and pepper.

Remove pan from heat. Carefully fold sour cream and spinach into ravioli until thoroughly combined with broth. Season with salt and pepper. TIP: You should have a thick, creamy sauce and wilted spinach. If the sauce is too thick, add a splash of water.

If you're not using an ovenproof pan, transfer mixture to baking dish. Sprinkle with Parmesan breadcrumbs, and broil until golden brown, 2-3 minutes.