Preheat the oven to 350 degrees F. Lightly grease a 3-quart deep casserole. Set aside.
Toss the parsnips, carrots, beets, rutabaga, pearl onions, and garlic together in a large bowl. Add the chard, tarragon, parsley, salt and pepper to taste, and 1/4 cup of the melted butter. Transfer the mixture to the prepared casserole and add the chicken broth. Cover the casserole tightly with aluminum foil.
Bake for about 35 minutes, or until all of the vegetables are tender. Remove the casserole from the oven and remove the foil. Do not turn the oven off.
Cover the vegetables with the mashed potatoes. Brush the top with the remaining two tablespoons melted butter and sprinkle with the breadcrumbs. Return to the oven for about 15 minutes, or until the potatoes are golden brown and crusty. Serve hot.
Coat the whole head or individual cloves with olive oil, wrap the garlic in aluminum foil, and roast it in a pan in a preheated 325-degree oven for about 1 hour, or until the flesh is very soft when pierced with a knife.
Copyright Charlie Palmer's Casual Cooking (Morrow, 2001)