Season steak with coarse salt and ground pepper. Heat a large skillet over medium-high. Add steak and cook until medium-rare, 3 to 5 minutes per side. Transfer to a plate to rest.
Reduce heat to medium and melt butter. Add Brussels sprouts and season with salt and pepper. Cook, stirring occasionally, until crisp-tender, 3 to 5 minutes. Remove from heat and stir in almonds, soy sauce and any dripping from the meat.
Serve steak over Brussels sprouts.