Sautéed mushrooms served over toast is a classic British dish. In this version I add more of a French twist, reducing a bit of white wine with the mushrooms and adding crème fraîche for a creamier finish inspired by one of my favorite mushroom pasta recipes.
Heat a large sauté pan over medium heat, add 3 tablespoons (26g) of the olive oil and heat through. Working in batches if needed to not overcrowd the pan, add the mushrooms and sauté until they reduce in size, about 3 minutes.
Add 2 tablespoons (28g) of the butter, thyme sprigs and season with salt and pepper. Continue to sauté until the mushrooms release their water and are golden brown, about an additional 3 minutes. If cooked in batches add all mushrooms back to the pan.
Add the shallots and cook, stirring occasionally, until the shallots are tender, about 3 minutes. Stir in the miso paste.
Add the wine and let reduce by about half, about 4 minutes. Remove the mushrooms to a medium bowl and set aside.
Clean the cast iron pan and return it to medium heat. Add the remaining oil and heat through then add the remaining butter and allow to melt. Arrange the pieces of bread to the pan and fry until golden brown and toasted, about 2 minutes.
Top the toasted slices of bread with the mushroom mixture and spoon any extra sauce over the top. Garnish with the herbs and pickled shallots (optional).