In a sauce pan, combine the shallots, garlic, wine, and lemon. Bring the liquid up to a boil. Stir in the dill and cook for 3 minutes. Whisk in the mustard and cream, continue to cook for 2 minutes. Whisk in the butter a cube at a time, until all the butter is incorporated. Season with salt and pepper. Place the grilled vegetables on the platter. Lay the cakes directly on top of the vegetables. Drizzle the sauce over the cakes. Garnish with the sizzled leeks and Essence.