Arrange a rack in the middle of the oven and heat to 400°F.
Place the broth, wine, cornstarch, garlic, thyme, salt, and pepper in a 9x13-inch baking dish and whisk until the cornstarch is fully dissolved. Add the ravioli and arrange in an even layer. Place the lemon slices evenly over the ravioli. Dot the top of the casserole with the butter. Cover the baking dish tightly with aluminum foil.
Bake for 30 minutes. Uncover and sprinkle with the peas. Bake uncovered until the sauce bubbles around the edges, about 10 minutes more. Sprinkle with the parsley and let sit 5 to 10 minutes for the sauce to thicken slightly before serving.
