Pat the steak dry with paper towels. Rub with olive oil, then season generously with kosher salt and freshly ground black pepper.
Heat a skillet over medium-high heat until hot. Sear the steak for 3–4 minutes per side, or until it reaches an internal temperature of 130°F for medium-rare. Transfer to a cutting board and let the steak rest for 8–10 minutes.
Preheat the oven to 400°F. Arrange the baguette slices on a baking sheet and brush both sides lightly with olive oil. Bake for 6–8 minutes, flipping halfway through, until the slices are crisp and golden.
In a small bowl, combine the whipped ricotta, lemon zest, chopped fresh basil, and salt until smooth.
Thinly slice the steak against the grain. Spread a layer of the ricotta mixture over each toasted baguette slice. Top with a slice of steak, a few microgreens, and a drizzle of balsamic glaze. Finish with a sprinkle of sea salt. Serve immediately.