sourdough bread, cut into ¾" cubes
extra-virgin olive oil
cremini mushrooms, de-stemmed, quartered or halved
pepper, freshly ground
leeks, white and light green parts halved and thinly sliced
celery, thinly sliced
thyme, finely chopped 1T of leaves
red pepper flakes
low-sodium vegetable broth
flat-leaf parsley, chopped
Preheat oven to 300°. Divide sourdough bread between two baking sheets. Spread in a single layer.
Bake until crisp and dried all the way through (~35 mins). Stir a few times. Transfer to a large bowl.
In a large skillet, heat 5T of extra-virgin olive oil over medium-high. Add cremini mushrooms, kosher salt and pepper. Cook and stir occasionally until tender and beginning to brown (8 mins). Add to large bowl.
Heat 2T extra-virgin olive oil to cook leeks, celery, and thyme sprigs (not leaves) until soft (4 mins). Add to cook garlic, thyme leaves, red pepper flakes for 1 min.
Deglaze skillet by adding ½ cup low-sodium vegetable broth to cook until evaporated (~2 mins). Discard thyme sprigs. Add to large bowl. Cool for 5 mins.
Brush a 2 to 2½-quart baking dish with extra-virgin olive oil.
Increase oven temperature to 375°.
In the large bowl, toss to combine flat-leaf parsley. Drizzle and stir with remaining low-sodium vegetable broth to moisten.
Transfer to baking dish. Loosely cover with parchment paper and bake for 20 mins.
Remove parchment paper and continue baking until golden on top (25 mins). Sprinkle with more flat-leaf parsley if desired.