01 - Preheat oven to 400°F.
02 - Slice tops off garlic bulbs to expose cloves. Drizzle with 1 tbsp olive oil, wrap in foil, and roast for 30 minutes until soft and golden.
03 - Pat flank steak dry and rub with 1 tbsp olive oil, salt, and pepper.
04 - Heat large ovenproof skillet over medium-high heat. Sear steak 3-4 minutes per side until browned. Transfer to oven and roast 6-8 minutes for medium-rare.
05 - Remove steak from oven, transfer to plate, and tent loosely with foil. Let rest for 10 minutes.
06 - Squeeze roasted garlic cloves into small saucepan. Add broth and simmer over medium heat, whisking to break up garlic.
07 - Add cream, butter, Dijon mustard, and lemon juice. Simmer gently 2-3 minutes, whisking until smooth and slightly thickened. Season with salt and pepper.
08 - Slice flank steak thinly across the grain. Spoon roasted garlic sauce over steak and garnish with fresh parsley if desired.