Australian Wagyu Carpaccio, Horseradish, Oyster Mushrooms, Squash Pickles and Seeds, Nasturtiums, and Ranch Dressing
For the Australian Wagyu Carpaccio:
Heat cast iron skillet over high flame until very hot. Rub beef with oil and season generously with salt and pepper. Quickly sear bison on all sides, about 30 to 45 seconds per side. Remove from heat and place beef on sheet tray with rack. Transfer to freezer until firm but not frozen.
For the Pickled Squash:
In a saucepan, combine vinegar, sugar, water, and salt and heat until salt dissolves; chill quickly. Pour brine into vacuum bag with squash and seal on high. Refrigerate at least 1 hour before serving.
For the Oyster Mushrooms:
In a heavy pan over medium high flame, heat oil until almost smoking. Add mushrooms in a single layer and brown. Avoid moving, shaking, or stirring the pan for at least 1 minute. Give the mushrooms a good stir. Add butter, thyme, and bay and cook until mushrooms are golden and butter is fragrant and frothy. Remove from heat and drain mushrooms on paper towels. Season with salt and pepper. Reserve warm.
For the Ranch:
In a blender, combine garlic, yolk, Dijon, and lemon and blend on high speed until yolks are pale. Reduce speed to medium and slowly drizzle in salad oil. When mixture emulsifies, reduce speed to lowest setting and blend in buttermilk. Season with salt and lots of black pepper.
To Assemble and Serve:
Remove Australian Wagyu Carpaccio from freezer and slice thinly with a sharp knife. Arrange carpaccio on chilled serving plate. Scatter Oyster Mushrooms on the carpaccio. Lightly crush pumpkin seeds spread around plate. Spoon a few teaspoons of Ranch on and around Carpaccio. Finish with nasturtium leaves and flowers, olive oil, and salt.