Heat oven to 350 degrees.
Remove the crust from the bread and cut it into 1-inch cubes. Spread out onto a baking sheet pour 1 tablespoon of olive oil onto the bread and squeeze so that the bread absorbs the oil, bake in the oven for 30 to 40 minutes until the bread is dried out and you have croutons. Set aside in a large bowl.
In a large wide bottomed pan heat 2 tablespoons of olive oil and vegan butter over medium heat and add your garlic, cook for 1 minute. Add your leek to the pan and cook for 5 to 10 minutes until soft and fragrant, season with salt and pepper. Add your mushrooms and thyme and continue to cook for 10 to 15 minutes until the mushrooms have released their juices and the juices have evaporated. Season with more salt and pepper.
Add the wine and cook for 5 minutes until the liquid has almost all reduced, fold in the sage, and remove from the heat. Pick out the thyme sprigs and spoon the mushroom mixture over the bread. Stir in the cup of veggie stock, the mixture should be moist and soft.

Butter the bottom of your 8 x 10 baking pan. Transfer the bread mixture to the prepared baking dish. Drizzle with 2 tablespoons of melted vegan butter and bake in the oven until golden, around 40 minutes.