In a skillet, melt 2 tablespoons of butter over medium heat. Add the finely chopped mushrooms and cook until they are soft and the moisture has evaporated, about 5-7 minutes.

Add Garlic and Seasonings

Stir in the minced garlic and cook for an additional 1-2 minutes until fragrant. Add lemon juice, fresh dill, salt, and black pepper. Mix well and remove from heat.

Prepare Escargot Shells

If using escargot shells, rinse them thoroughly. If using a baking dish, prepare it by greasing with remaining butter.

Fill Escargot

Place escargot in the shells or baking dish and spoon the mushroom mixture evenly into each escargot shell or over the escargot in the dish.

Bone Marrow Jus Preparation

Roast the Bone Marrow

Preheat your oven to 400°F (200°C). Place the bone marrow in a baking dish and roast for about 15-20 minutes until it is soft and starting to separate from the bone.

Make the Jus

In a saucepan, combine the roasted bone marrow, diced shallots, beef stock, and a sprig of thyme. Bring to a simmer and let it reduce for about 10 minutes. Season with salt and black pepper to taste.

Final Assembly

Bake the Escargot

Preheat the oven to 375°F (190°C). Bake the filled escargot for about 10-12 minutes until hot and bubbling.

Serve

Plate the escargot and spoon the bone marrow jus over the top. Garnish with additional dill if desired, and serve immediately.