Cook 1 thinly sliced chile de arbol in 1/4 cup olive oil in a pot over medium heat until toasted, 2 to 3 minutes. Add the grated zest of 1 lemon, the juice of 2 lemons and 6 tablespoons butter and stir until melted. Toss with 12 ounces cooked linguine, adding up to 1 cup pasta-cooking water to loosen the sauce. Stir in 1/2 cup grated parmesan and season with salt. Top with 1 more crumbled chile de arbol.