In a saucepan, bring the milk to a boil. Remove the saucepan from the heat. Add the coffee. Cover and let steep for 10 minutes. Line a sieve with two layers of cheesecloth. Strain the milk. Set aside.
In a saucepan, brown the onions over low heat in the butter until caramelized. The onions caramelize slowly and must be completely soft. Sprinkle with the flour. Blend well. Add the milk and bring to a boil.
In a blender, purée until smooth. Season with salt and pepper. Keep warm.
In a small saucepan, bring the milk and sesame oil to a boil. Remove from the heat. Using a hand blender, foam the milk.
Pour the cream of onion soup in espresso cups. Top with milk foam. Season with pepper.
Foam the milk a second time if necessary.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.