In a saucepan, melt 2 tablespoon salted butter over medium-high heat.
Stir in ½ cup lemon juice, 1 teaspoon grated lemon zest, 3 minced garlic cloves, ½ teaspoon salt, and ¼ teaspoon black pepper. Cook for 1–2 minutes, allowing the flavors to combine.
Add 6 cups broccoli florets to the saucepan. Stir to coat the broccoli in the lemon butter sauce. Cook over low heat until the broccoli is heated through and tender when poked with a fork, about 5–7 minutes.
Taste and season with additional salt and pepper if needed.