Wash mushrooms by using a damp paper towel & then slice them into 1 inch thick rounds with a criss-cross pattern on the top and bottom of each.
Whisk together the miso paste, tamari/soy sauce, sesame oil, sugar, rice vinegar, ginger, & garlic. Pour the marinade over the sliced mushrooms and let it sit for at least 15 minutes up to an hour. Flip them half way through marinating.
Heat up a pan & add the olive oil & vegan butter. Add the mushroom rounds & cook them flipping half way through until lightly seared on each side. I cooked mine in two batches so it wouldn’t crowd the pan. Once they are cooked, add the minced garlic to the pan & sauté it for 30 seconds.