Steam the broccoli florets until they are exceptionally tender, easily pierced with a fork. Once done, roughly chop them and set aside.

Fill a large pot with 8 cups of water, add 1 tablespoon of salt (measured precisely), and bring to a boil. Cook the pasta according to package instructions until al dente. Reserve one cup of the hot pasta water before draining.

In a wide, deep pan, heat the olive oil over medium heat. Add the shallot, garlic, and chili flakes, sautéing until the shallot turns translucent and the garlic becomes fragrant and golden, about 3 minutes. Stir in the anchovy paste (or miso paste), ensuring it melds into the oil and aromatics.

Add the steamed broccoli along with salt, pepper, and broth. Bring the mixture to a gentle simmer. Using a metal spatula, begin breaking the broccoli into smaller bits. As it softens, continue mashing it down, gradually transforming it into a textured sauce. Allow it to cook down, adding extra liquid if needed to maintain a saucy consistency.

Mix in the lemon zest and pecorino cheese, stirring until well incorporated. Let the mixture simmer gently over low heat until it thickens and about half the liquid evaporates, approximately 10 minutes.

Using an immersion blender, blend the sauce directly in the pan while adding the chopped baby spinach. This step enhances the color and smoothness. If a smoother texture is preferred, transfer the mixture to a blender instead. The olive oil contributes to a luscious, creamy finish.

Toss the cooked pasta into the sauce, stirring well. Adjust the consistency by incorporating small amounts of the reserved pasta water until the sauce clings to the pasta while remaining velvety.

Taste and adjust the seasoning, adding more salt, black pepper, or chili flakes as needed. For extra richness, drizzle in a bit more olive oil or melt in a small pat of butter.

Divide into serving bowls and finish with your choice of garnishes—extra pecorino, a sprinkle of lemon zest, fresh basil, toasted pine nuts, or a drizzle of truffle oil. Serve immediately.