Preheat oven to 300ªF. (My oven is cooler than most I think, so if your oven runs hot, maybe go to 275ºF)

Spread out bread onto a large rimmed baking sheet and bake for 30 minutes, turning halfway to dry out. You'll want them to be light and crispy, but not browned at all. If you need to use two baking sheets, rotate pans halfway through to ensure even heat distribution.

Remove from oven and set aside and raise oven temperature to 350ºF.

Over medium heat, melt butter in a pot large enough to hold all the bread.

Add chopped leeks and apples and cook in butter for about 5 minutes, until apples are softened.

Pour in vegetable broth, fresh rubbed thyme (if desired) and flax egg and stir until combined.

Add the dried bread cubes and stir until all the liquid is combined. It might seem like there's too much bread, but keep stirring.

Transfer to a lightly greased casserole dish and cover tightly with foil.

Bake for 45 minutes covered, then uncovered fro 10-15 minutes until the top is golden.

Serve on the side of your favourite holiday dishes and gravy!