Rinse the Brussels sprouts under cool water, then pat them very dry with a clean kitchen towel. Trim off the tough stem ends and remove any yellowed or ragged outer leaves. Dry sprouts brown better and get crispier at the edges.
1 1/2 pounds fresh Brussels sprouts
Thinly slice the Brussels sprouts into shreds. You can use a sharp chef’s knife to slice each sprout from top to bottom, the slicing blade of a food processor for faster prep, or a mandoline slicer (use a guard and take care). Aim for thin, mostly even pieces so they cook quickly and evenly.
1 1/2 pounds fresh Brussels sprouts
Place a large, wide skillet (about 12 inches, stainless steel or cast iron) over medium-high heat. Add the olive oil and heat until it shimmers. A shred of Brussels sprout should sizzle when it hits the pan.
3 tablespoons extra-virgin olive oil
Reduce the heat slightly to medium. Add the minced garlic to the hot oil and cook, stirring constantly, for about 30 seconds, just until fragrant. Do not let the garlic brown deeply or it can become bitter.
3 cloves garlic, 3 tablespoons extra-virgin olive oil
Add the shaved Brussels sprouts to the skillet and toss to coat them in the garlicky oil. Spread them into an even layer and let cook without stirring for 1–2 minutes so the bottom layer begins to brown.
1 1/2 pounds fresh Brussels sprouts
Sprinkle in the kosher salt, black pepper, and red pepper flakes (if using). Toss well to coat. Continue cooking for 6–8 minutes total, stirring every 1–2 minutes, until the sprouts are mostly tender with some crispy, caramelized edges. If the pan looks dry, add a small drizzle of additional olive oil.
1/2 teaspoon kosher salt, 1/4 teaspoon freshly ground black pepper, 1/4 teaspoon red pepper flakes, 3 tablespoons extra-virgin olive oil
Reduce the heat to low. Add the lemon zest and 1 tablespoon of lemon juice to the skillet and toss well. Taste a few shreds; if you prefer a brighter, more lemony flavor, add up to 1 tablespoon more lemon juice.
1 lemon
Turn off the heat. Sprinkle the grated parmesan over the sprouts and add the butter, if using. Toss until the cheese softens and lightly coats the sprouts and the butter melts. If using toasted nuts, fold them in now for extra crunch.
1/2 cup parmesan cheese, 1 tablespoon butter, 2 tablespoons chopped toasted nuts
Taste and adjust seasoning with additional salt, pepper, or lemon juice as needed. For extra richness, you can finish with a light drizzle of olive oil. Serve warm straight from the skillet or transfer to a serving dish. The sprouts are also good at room temperature, which is handy for holiday meals.
1/2 teaspoon kosher salt, 1/4 teaspoon freshly ground black pepper, 3 tablespoons extra-virgin olive oil, 1 lemon