Rinse the Brussels sprouts under cool water, trim the stem ends, and remove any yellow or damaged outer leaves. Halve them lengthwise (quarter any very large sprouts so they cook evenly). Pat completely dry so they caramelize instead of steaming.
1 1/2 pounds Brussels sprouts
In a large oven-safe skillet (10–12 inch cast iron or stainless steel), heat the olive oil and butter over medium-high heat. When the butter foams, add the Brussels sprouts cut-side down in a single layer without overcrowding. Sear for 5–7 minutes, with minimal stirring, until the cut sides are deeply golden brown.
1 1/2 pounds Brussels sprouts, 2 tablespoons unsalted butter, 2 tablespoons olive oil
Sprinkle the Brussels sprouts with kosher salt, black pepper, onion powder, and smoked paprika (if using). Stir and cook for another 3–4 minutes, allowing the sprouts to soften while still holding their shape. Reduce the heat slightly if they brown too quickly.
1 1/2 pounds Brussels sprouts, 3/4 teaspoon kosher salt, 1/2 teaspoon black pepper, 1/2 teaspoon onion powder, 1/2 teaspoon smoked paprika
Stir in the minced garlic and cook for 30–60 seconds, just until fragrant. If the pan looks dry, add a small splash of olive oil to prevent the garlic from burning.
3 cloves garlic, 2 tablespoons olive oil
Reduce the heat to medium-low. Pour in the heavy whipping cream and stir well, scraping up any browned bits from the bottom of the pan with a wooden spoon so they incorporate into the sauce.
1 cup heavy whipping cream
Add the cubed cream cheese. Stir gently and continuously for 2–3 minutes, until the cream cheese is fully melted and the sauce is starting to thicken and turn smooth and silky.
2 ounces cream cheese
Stir in the grated Parmesan and half of the shredded mozzarella. Continue stirring until the cheeses are fully melted and the Brussels sprouts are well coated in a thick, creamy sauce. Taste and adjust with additional salt and pepper as needed. Add red pepper flakes if you’d like a bit of heat.
1/2 cup Parmesan cheese, 3/4 cup mozzarella cheese, 3/4 teaspoon kosher salt, 1/2 teaspoon black pepper, 1/4 teaspoon red pepper flakes
Turn off the heat and stir in the lemon juice to brighten the flavors. Smooth the sprouts and sauce into an even layer, then sprinkle the remaining mozzarella evenly over the top.
1 tablespoon lemon juice, 3/4 cup mozzarella cheese
Position an oven rack a few inches below the broiler and preheat the broiler to high. Place the oven-safe skillet under the broiler for 3–5 minutes, just until the top is bubbly and lightly browned. Watch closely so the cheese doesn’t burn. (If your skillet isn’t oven-safe, transfer the mixture to a small baking dish before topping with cheese and broiling.)
Remove the skillet from the oven and let the creamed Brussels sprouts rest for about 5 minutes so the sauce can thicken slightly. Garnish with chopped fresh parsley and crumbled bacon, if using. Serve warm as a keto side dish alongside your favorite protein.
2 tablespoons fresh parsley, 3 strips bacon