Slice the mushrooms into 2-inch thick pieces.

Heat a large non-stick pan or skillet over medium. Once hot, brush or spray a thin layer of oil.

Place the mushrooms flat side down first. Leave the mushrooms untouched for 3-4 minutes or until lightly brown. Flip over and repeat for the remaining side. You may need to do this in multiple batches depending on the size of your pan.

Meanwhile, mix together the miso paste and water until the miso paste is diluted.

When the mushrooms have a good sear, add the sake, mirin, soy sauce, and sugar. Allow for the sake and mirin to evaporate.

Pour the miso paste-water mixture. Leave the mushrooms to simmer in the miso-based sauce for 3-4 minutes or over medium heat. Leave the mushrooms at a gentle simmer until the sauce has reduced and it turns into a thicker glaze-like consistency.