How to Make It
Place the onion rings in a large heatproof jar or bowl. In a medium saucepan, combine the balsamic vinegar with the mustard seeds, honey and bay leaves. Bring to a boil, reduce the heat to low and simmer for 15 minutes. Pour the hot liquid over the onion rings, pressing to submerge them. Cover and refrigerate overnight.
Preheat the oven to 375°. In a medium roasting pan, toss the beets with the olive oil and water. Cover tightly with foil and braise until tender, about 45 minutes. Let the beets cool in their braising liquid. Peel the beets, return them to the liquid and season with salt and pepper.
Meanwhile, in a small saucepan, boil the red wine with the sugar over high heat until reduced to a syrup, about 10 minutes. Let the wine syrup cool.
In a bowl, whisk the crème fraîche with the lemon juice and zest and season with salt. Spread the crème fraîche on a platter. Mound the beets on the crème fraîche and drizzle with their cooking liquid. Garnish with the pickled onion rings and watercress; drizzle with the wine reduction and serve.