Step 1

Preheat oven to 425 degrees, and line a baking sheet (with a rim) with aluminum foil. Alternatively, spray a baking sheet with non-stick cooking spray.

Step 2

Trim brussels sprouts, removing any loose leaves from the outside. Slice in half, lengthwise.

Step 3

Add oil, vinegar, garlic, mustard, salt and pepper to a mixing bowl and whisk until well combined. Add brussels sprouts and toss to ensure they're coated. Spread out on baking sheet and scatter butter throughout sprouts.

Step 4

Bake for 20-25 minutes, flipping brussels sprouts over about halfway through cooking time.