Preheat oven to 325˚F.
Heat a soup pot over medium to medium-high heat. Melt butter and add onions, bay, ground thyme, salt and pepper. Cook onions until very soft and light caramel in color, 20 minutes.
Add apples, stir to combine and cook 10 minutes more. Stir in balsamic drizzle, if using, add cider and stock. Bring to a boil and let reduce, about 10 minutes.
For the croutons, in a small saucepot, heat EVOO with hot sauce and crushed garlic clove. Let oil infuse a couple of minutes then brush the bread slices. Arrange slices on a cooling rack set over baking sheet and bake until crisp, 5-6 minutes. Top toast with mounds of cheese and a sprinkle of fresh thyme. Bake 2 minutes more to melt the cheese.