Yields 2 servings
1 Head cauliflower
1/2 Pound mushrooms, cremini
3/4 Pounds beef, New York strip
1 to taste pepper, black, ground
1 to taste salt, Kosher
1 Tbls oil, olive
3 Tbls butter, unsalted divided
1 Tbls vinegar, balsamic
1/2 Bunch parsley, flat-leaf
Fill a medium saucepan about halfway with water, cover and bring to a boil.
Wash cauliflower and cut off the leaves. Separate into small florets and cut the thick stem into smaller pieces; transfer to a bowl. Add to boiling water and cook until very tender, 10 to 15 minutes. Drain in a colander, return to saucepan, and cover.
Wash and slice mushrooms.
Heat a heavy skillet over medium-high heat.
Generously season steak with salt and pepper. Coat skillet with oil. Add steak and cook until desired doneness, 2 to 5 minutes per side. Transfer to a plate and loosely cover with foil.
Once steak has been transferred, reduce heat to medium and add 1 tablespoon butter and mushrooms to skillet. Cook, stirring occasionally until tender, 3 to 4 minutes. Add vinegar and season with salt and pepper; cook until reduced, 2 to 3 minutes more. Remove from heat.
Wash and dry parsley. Shave leaves off stems; discard stems and mince the leaves.
Add water, 2 tablespoons butter, salt and pepper to taste, and about 1/2 the parsley to cauliflower. Blend using an immersion blender or potato masher.
To serve, place puree on plate, top with steak and cover with mushroom sauce. Sprinkle with remaining parsley.