Preheat oven to 450°. In a large bowl, whisk together oil, 1 tbsp. lemon juice, curry powder, salt, and cayenne if you like. Add cauliflower slices and toss to coat. Spread cauliflower in a single layer in a large baking pan.
Bake until cauliflower is tender, chewy, and brown, 25 to 30 minutes. Sprinkle with remaining 1/2 tsp. lemon juice and garnish with cilantro.
Note: Nutritional analysis is per serving.