Preheat your oven to 350°F (175°C) and grease a muffin tin.
In a large bowl, combine the bread cubes, chopped onion, celery, sage, thyme, salt, and pepper.
Pour in the vegetable broth and mix gently until the bread is evenly moistened.
Fold in the cheese if using, and then let the mixture sit for about 10 minutes.
Spoon the mixture into the prepared muffin tin, filling each cup about 2/3 full.
Use your thumb to make a small well in the center of each muffin to hold gravy later.
Bake in the preheated oven for 20-25 minutes, or until golden brown.
Remove from the oven and let cool slightly before removing from the tin.
Carefully fill each muffin with warm gravy just before serving.
