In a blender, puree 6 tbsp. oil, the vinegar, herbes de Provence and half the garlic. Rub 2 tbsp. of the mixture on the steaks. Transfer the remaining mixture to a small bowl. Stir in the parsley; season with salt and pepper.
In a medium saucepan, heat the remaining 3 tbsp. oil over medium-low. Add the shallots and remaining garlic. Cook, stirring often, until soft, about 5 minutes. Add the beans, stock and oregano. Simmer over medium-high until the liquid reduces slightly, about 3 minutes. Transfer to a blender and puree; season.
Preheat a grill pan or skillet over medium-high. Season the steaks and cook, 6 to 7 minutes per side for medium-rare. Let rest 5 minutes, then thinly slice. Divide the bean puree and steak among plates; drizzle the meat with the parsley mixture.