Ingredients

Lobster and Sauce

• 2 cooked and shelled 2 lb lobsters (tails cut lengthwise in half and claws left whole) 
• 125 ml (1/2 cup) Blanche de Chambly beer 
• 200 g unsalted butter 
• 1 small French shallot, finely chopped 
• 60 ml (1/4 cup) 15% cream 
• 1 tsp Dijon mustard 
• 2–3 sprigs fresh tarragon 
• 1 tsp lemon juice 
• Salt and pepper 

Tarragon Mayonnaise

• 1 whole egg 
• 1 egg yolk 
• 1/2 cup sunflower oil, or more as needed 
• 3 sprigs fresh tarragon, leaves removed 
• Zest of 1 lemon 
• Juice of half a lemon 
• Salt and pepper 

For Serving

• 4 large thick slices of brioche or milk bread 
• Chives, finely chopped 
• Fresh tarragon leaves 
• Lemon zest 
• Flaky salt

1. Prepare the tarragon mayonnaise, using an immersion blender, blend the eggs and oil in a tall container (such as a measuring cup) until the mayonnaise thickens. Add the lemon zest, lemon juice, and tarragon leaves. Blend again and add more oil if the texture is too runny. Season with salt and pepper, then set aside. 
2. Prepare the sauce, in a saucepan over medium heat, melt the butter. Let it cook until it turns a brown butter color, about 3 to 4 minutes, stirring frequently. Add the shallot and cook for 1 minute. Pour in the Blanche de Chambly beer and let reduce for about 1 minute. Whisk in the Dijon mustard, then add the cream. Add the lemon juice and season with salt and pepper. Add the lobster pieces and warm through for a few minutes. 
3. Assembly, slice the brioche buns and toast them in a pan with a little butter until golden brown and crispy. Place the bread on a plate and top with two pieces of lobster. Spoon some sauce over top and garnish with chives and fresh tarragon. Serve the mayonnaise on the side.