In a skillet, heat the extra-virgin olive oil and garlic over medium heat. Once the pan is hot and the garlic fragrant, add the mushrooms. Add the ginger and salt. Stir well to coat. Cook over medium heat until the mushrooms are softened, about 10 minutes. Stir occasionally. If the mushrooms begin to stick to the pan, add a splash or two of water to deglaze the pan. Remove the mushrooms from the heat.

Cut the brie into thin slices. Set aside.

Take one piece of bread. Smear a generous portion of mayonnaise on one side and a generous smear of whole grain mustard on the other side. With the mayonnaise side facing down, add a layer of brie on top of the mustard. Place a spoonful of mushrooms on top of the mushrooms. Top the mushrooms with the torn basil. Repeat this step until the amount of sandwiches desired is constructed. These sandwiches should be “open-faced” at this step. The top piece will be added later in the cooking process.

Meanwhile, in a cast iron skillet, melt a thin slice of butter over medium heat. Once the butter is melted, swirl the butter in the pan to evenly coat the skillet.

Once the pan is hot, move the opened-face sandwiches to the skillet (two to three pieces of bread at a time, depending on the size of the pan).

Add another layer of brie to top each sandwich on the skillet.

Take the second piece of bread and add a generous layer of mayonnaise to one side. Place this slice on top of the “open-faced” sandwich that is now cooking in the skillet. The mayonnaise side should be facing up. Repeat this step until all sandwiches are now topped with a slice of bread.

Continue to cook the sandwich until the bottom side is golden brown, about 5-8 minutes. Gently flip the sandwich and cook the remaining side until golden and the cheese is melted. Serve immediately.