In a pot, slowly fry the Yellow Onion (3) in the Extra-Virgin Olive Oil (1 1/2 teaspoon) until translucent. Season with the Salt and Pepper (to taste). Add the sliced Garlic (2 clove) and the Chicken Stock (1 liter) and simmer for a few moments.
Throw in the Bay Leaf (2), Fresh Thyme (2 sprig), and Dry Red Wine (250 milliliter). Unwrap the Beef Stock Cube (1) and, using your fingers, crumble into the soup. Give it a good stir and allow to simmer and reduce slightly for 20 minutes.
Preheat the oven to 190 degrees C (375 degrees F) and arrange the Beef Marrow Bones (8) on a lined baking sheet.
Season with Salt and Pepper (to taste) and Fresh Thyme (1 sprig). Roast off the bones for 10 to 15 minutes.
Either serve bone marrow as a starter with melba toast or as part of the soup along with a slice of toasted sourdough topped with melted Gruyere or Stilton. Enjoy!