Heat the oil in a sauté pan, add the butter and allow it to melt, then add the whole echalions, thyme, bay leaves, a pinch of salt and some black pepper. Cook over a low heat for 10-12 minutes, moving the echalions around the pan every few minutes until golden brown.
Halfway through the cooking time, add the sugar to help caramelise the echalions. Pour in the vinegar and red wine and simmer until reduced by two-thirds, then add the stock and simmer for about 10 minutes until reduced and sticky. Remove the thyme and bay leaves before serving.