Preheat your oven to 400°F (200°C). Wrap whole heads of fresh garlic in aluminum foil. Roast in the oven for about 40 minutes, until soft and golden.

After cooling, unwrap the foil and squeeze the roasted garlic cloves into a blender.

Add Dijon mustard, grated Parmesan cheese, and the juice of half a lemon. Blend until well combined.

With the blender running on low, slowly drizzle in about one cup of olive oil until the mixture is smooth and creamy.

Taste and season with salt and freshly cracked black pepper. Blend briefly to combine.

Transfer to an airtight container and refrigerate for at least 30 minutes before serving.