Combine beans & broth in a small saucepan. Bring to a boil, simmer, uncovered until beans are hot. Mash beans using a hand blender until smooth. Stir in parmesan, butter, salt & pepper. Stir until well combined & cheese & butter are melted; keep warm.
Sprinkle steaks with salt & pepper & a drizzle of olive oil. Cook in a medium cast iron or non-stick frying pan for 5 minutes. Turn & cook a further 3 minutes for medium rare (135 – 140F). Remove to plate; cover & keep warm.
Melt butter in the same pan over medium-high heat. Add mushrooms, garlic & a pinch of salt & pepper. Cook for 5 minutes, stirring once or twice, until browned & softened. Add mustard & wine; cook until liquid has reduced by half. Add 1/2 cup of cream. Bring to a boil. Cook for 2 minutes or until thickened slightly, adding a little extra cream if you prefer the sauce a little runnier. Taste & season with salt & pepper if needed.
To serve, place a spoonful of white bean mixture onto a plate or shallow bowl. Add steak & spoon over the mushroom sauce. Serve with beans, if desired. Serves 2.