Pulse bread in a food processor to form fine crumbs. Place in a dish.
Heat a large skillet over medium-high heat. Coat with 1 Tbsp olive oil & 1 Tbsp vegan butter. Add onions and mushrooms; sauté 10 minutes. Stir in thyme and garlic. Cool mixture 10 minutes; stir in cheese, 1/4 teaspoon salt, and 1/4 teaspoon pepper.
Lay yellow squash/zucchini on its side and cut a very thin layer off of opposite sides of each so they lay flat in a skillet (see video in post for example). Cut a slit through thickest portion of each lengthwise to form a pocket. i cut them from 1/2 inch from the end all the way down to 1/2 inch from the other end to get as much stuffing & flavor through out each. Then pop them in the microwave for 60 secs just to make them a little more flexible for stuffing.
Stuff each with mushroom mixture. Sprinkle squash with salt and pepper. Place flour in a shallow dish. Place silk creamer in a shallow dish. Place squash in flour on both sides using tongs or fingers, sprinkle each side with flour if need be. Place in silk creamer on both sides; Place in breadcrumbs on both sides.
Heat 1 Tbsp olive oil in skillet over medium-high heat. Add squash; cook 2 minutes on each side or until browned. Place in baking dish greased with 1 Tbsp vegan butter. Bake at 350° for 15 minutes