1/4 cup grated Parmigiano Reggiano (60 milliliters)
Whisk together milk, eggs, salt and pepper until well blended.
Butter a 32 x 20 x 10 centimeter oval casserole dish (or 12-cup baking dish). Sprinkle with a layer of bread cubes and diced celery. Top with one-third each of the grated gruyere cheese and herbs and season. Repeat layering with more celery, bread and herbs, making sure to season each layer.
Pour egg mixture over top. Cover and refrigerate for at least two hours or for up to one day to let egg mixture soak into bread.
Preheat oven to 375 degrees F.
Brush top with melted butter and sprinkle pudding with Parmesan cheese. Bake on middle rack for about 35-40 minutes or until centre is set and top is golden.