Heat 3 tablespoons butter with 1 tablespoon olive oil in a large stockpot over high heat. Add the wild mushrooms
and cook until the mushrooms are golden brown and their liquid has evaporated, about 8 to 10 minutes. Transfer the mushrooms to a bowl.
Heat 1 tablespoon butter with 1 tablespoon oil in a medium saucepan
over medium-high heat. Add the onion and cook until soft. Add the cremini mushrooms and cook until golden brown, about 4 to 5 minutes. Sprinkle flour over mushrooms and cook for 2 minutes. Add the stock and porcini powder and cook for 20 minutes. Season, to taste, with salt and pepper. Strain the stock through a strainer into the stockpot that you sauteed
the wild mushrooms in and discard the onion and mushrooms.
Cook stock over medium heat until thickened slightly and then stir in the sauteed wild mushrooms and cook for 15 minutes. Season, to taste, with salt and pepper.
While the soup is cooking, heat the canola oil in a high sided saute pan over high heat until the oil begins to shimmer. Carefully add the ham, in batches, and cook until crispy, about 45 seconds to 1 minute. Drain
on a plate lined with paper towels.
Ladle the soup
into bowls, add a handful of arugula, top with a slice of the crispy ham, and drizzle
with a teaspoon of white truffle oil.