5 tablespoons extra-virgin olive oil
2 garlic cloves, minced
½ cup mayonnaise
1 teaspoon grated lemon zest plus 2 tablespoons juice
½ teaspoon minced fresh thyme
Salt and pepper
1 pound Brussels sprouts, trimmed and quartered through stem
2 teaspoons cornstarch
1. Microwave 2 tablespoons oil and garlic in small bowl until garlic is fragrant and just beginning to color, about 1 minute. Whisk mayonnaise, lemon zest and juice, thyme, 1/8 teaspoon pepper, and oil-garlic mixture together in bowl. Cover and refrigerate until ready to use.
2. Adjust oven rack to middle position and heat oven to 350 degrees. Spray rimmed baking sheet with vegetable oil spray. Toss Brussels sprouts and cornstarch in large bowl to evenly coat. Add remaining 3 tablespoons oil and toss thoroughly to coat all sides of sprouts. Transfer sprouts to prepared baking sheet and arrange cut side down in single layer.
3. Bake until sprouts are golden brown and crisp, about 45 minutes, stirring halfway through cooking. Transfer sheet to wire rack and season sprouts with ¼ teaspoon salt and ¼ teaspoon pepper, stirring to coat. Let cool for 5 minutes. Transfer to serving platter and serve with sauce.