01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease each cup.
02 - In a large skillet over medium heat, melt 1 tablespoon of the butter. Sauté the mushrooms and onions until tender and most moisture has evaporated, about 6 to 8 minutes. Add soy sauce and cook for 1 minute more. Remove from heat and allow mixture to cool.
03 - In a large mixing bowl, whisk together all-purpose flour, baking powder, baking soda, salt, and black pepper until evenly combined.
04 - In a separate bowl, combine whole milk, eggs, Greek yogurt, and the remaining melted butter. Whisk until the mixture is smooth and homogenous.
05 - Fold the wet ingredients into the dry mixture until just combined. Gently stir in the cooled mushroom mixture, grated cheese, spring onions, and 2 tablespoons furikake seasoning. Do not overmix.
06 - Spoon the batter evenly into the prepared muffin tin. Sprinkle additional furikake seasoning and toasted sesame seeds over each muffin.
07 - Bake in the preheated oven for 22 to 25 minutes, until muffin tops are golden and a toothpick inserted into the center comes out clean.
08 - Cool muffins in the tin for 5 minutes before transferring them to a wire rack. Serve warm or at room temperature.