Place a medium saute pan over medium-low heat. Add the butter and olive oil. Once the butter has melted, add the anchovies and saute until they start to break down, about 1 minute. Add the oregano, crushed red pepper and garlic and saute for 2 to 3 minutes to allow the anchovies to completely break down and the garlic to cook. Take the pan off the heat and allow to cool for 2 to 3 minutes. Stir in the lemon juice and parsley. Taste and season with salt and pepper if desired.
Heat a grill or grill pan to medium-high heat. Season both sides of the flank steak with a generous amount of salt and pepper. Brush the grill grates or grill pan with the canola oil. Grill the steak for 3 to 4 minutes per side for medium rare. Let rest for 5 minutes before slicing. Slice and top with the sauce.