Step 1

Make the Teriyaki sauce: Whisk together the soy sauce, mirin, maple syrup, 1½ tablespoons of water, and the ginger in a bowl until well combined.

Step 2

Make the sauce for rice bun: Whisk together mirin and soy sauce in a bowl until well combined.

Step 3

Make the sriracha mayo: Combine the mayonnaise and a big squeeze of sriracha in a bowl. Mix until combined, then add more sriracha to taste.

Step 4

Clean the mushrooms with a brush to remove any debris. Cut off the mushroom top and reserve that for another dish. Halve the stem crosswise. Fill a large saucepan with water. Bring to a boil, then season with salt. Add the stem pieces to the hot water. Boil for 5 to 8 minutes, until the skin turns from white to grayish. Transfer to the ice bath to cool. Drain and pat dry. Using a sharp knife, make a slit lengthwise, then continue to slice in a spiral motion to make a cutlet. Score one side to uncurl the cutlet. Pat dry again.

Step 5

Cook the mushrooms: Add a drizzle of oil to a large nonstick skillet over medium heat. Sear the cutlets over medium heat until browned on both sides, about 4 to 6 minutes total, pressing them down with a spatula if they start to curl up. To season, take a cutlet and dip into the teriyaki sauce and return it back to the pan and sear until browned and charred. Repeat with another baste if you’d like. Transfer the teriyaki mushrooms to a plate. Clean the skillet—we’ll be using it again in a bit.

Step 6

Shape the rice patties: Line a small, straight-sided bowl or ramekin (about 3 inches in diameter) with plastic wrap and add ½ cup of rice. Using the back of a spoon, tightly press the rice into a patty. Unwrap and set aside. Repeat with the remaining rice.

Step 7

Sear the rice patties: Set a lightly greased nonstick skillet over medium-low heat. Add as many rice patties as will comfortably fit. Cook undisturbed until browned, 5 to 8 minutes. Flip and cook this side for about 2 minutes before brushing the browned side with the teriyaki sauce and continue to cook for another 2 to 3 minutes until the other side is slightly charred, basting a couple more times along the way. Transfer the patties to a wire rack to cool. Repeat with the rest of the rice patties.

Step 8

Place a seared rice patty on a plate, then top with avocado slices and a nori sheet. Pile with 2 mushrooms cutlets and some sriracha mayo. Close with another rice patty. Repeat with the rest of the ingredients to make three more burgers.