Heat 1 teaspoon olive oil in a large pan over medium-high heat. Add mushrooms and salt. Saute until most of the water released from the mushrooms has evaporated, about 10 minutes. Transfer mushrooms to a bowl, reserving oil in the pan. Add leek, onion, carrot, and celery and reduce heat to medium. Cook and stir until vegetables are golden brown, 5 to 7 minutes. Add garlic, bay leaf, thyme, and coriander. Return mushrooms to the pan; cook and stir for 3 minutes. Add vinegar and cook 1 minute. Add stock and bring to a simmer for 1 more minute. Transfer contents of pan to a heat-resistant bowl and add 1/3 cup olive oil. Let sit 2 hours. Season with lemon juice, salt, and pepper. Preheat the oven to 350 degrees F (175 degrees C). Lay baguette slices on a baking sheet. Brush lightly with olive oil and season with salt. Bake in the preheated oven until golden, turning once, about 8 minutes per side. Lay toasted bread on a plate and spoon marinated mushrooms on top.