Pour enough oil into a medium pot so that the oil comes 3 inches up the sides. Heat the oil to 350 degrees.
While the oil is heating, whisk together the garlic, anchovies, serrano, red wine vinegar, honey, scallions, walnuts and extra-virgin olive oil in a bowl large enough to toss all of the Brussels sprouts. Keep the bowl near the stovetop.
Working in batches, deep-fry the Brussels sprouts until the edges begin to curl and brown, about 3 minutes. To the last batch, add the parsley and capers (stand back-the capers will pop and sputter!). Give the contents of the pot a stir. When the color of the parsley becomes a deeper, more saturated shade of green, about 30 seconds to 1 minute, remove the contents of the pot with a skimmer and place directly in the bowl of dressing. Toss to coat. Add salt and pepper to taste.
Photograph by Hallie Burton
Recipe courtesy Food Network Magazine, excerpted from Michael Symon's book Live to Cook (Clarkson Potter)