The night before, cut the sourdough into cubes and spread out on a cookie sheet. If possible, leave bread out overnight or bake at 150 degrees F for an hour until bread is crunchy stale, but not hard or browned at all.

The next day, preheat the oven to 350 degrees F. Butter a 9 x 9-inch baking pan and set aside.

In a very large, deep skillet or Dutch oven, melt 5 tablespoons butter over medium heat. Add onions and celery and cook until tender, about 10 minutes. Add the celery root and a generous sprinkle of sea salt, edge heat to medium-high (hot, but not enough that the butter is smoking) and cook 10 minutes longer, until pieces are tender and lightly browned on the edges. Pour in a splash of stock and scrape up any brown bits. Then add remaining stock, bring mixture to a boil, and simmer for 5 minutes. Turn heat off and stir in bread crumbs, minced herbs, and Meyer lemon zest and juice. Add chili powder, and sea salt and black pepper to taste.

Spoon into prepared baking pan, dot with remaining tablespoon butter, and slide into oven and bake for 35 - 45 minutes, or until the top of the stuffing is a rich golden brown and stuffing is piping hot.

Meanwhile, make the roasted Meyer lemons. Drizzle olive over lemon slices and arrange on a rimmed baking sheet.

Roast 10 minutes in a 350 degree oven, flip, and roast 10 minutes more. Cool and cut slices into half moons.

Before serving, tuck slices of roasted Meyer lemon throughout, and garnish stuffing with minced celery leaves, parsley, sage, and thyme leaves.