To cut nice, neat slices of roast, cook and refrigerate it the day before serving. Slice the roast cold, and reheat the slices in the sauce.

1 4 1/2-pound top or bottom-round beef roast, tied

Coarse salt and freshly ground pepper

4 tablespoons safflower oil

3 large onions, thinly sliced

6 cloves garlic, thinly sliced

1 tablespoon sugar, plus more if needed

1 cup red-wine vinegar

3 cups dry red wine, such as Zinfandel or Pinot Noir

8 sprigs thyme, plus more tiny sprigs, for serving

1/4 teaspoon whole black peppercorns

6 whole juniper berries

3 dried bay leaves

2 whole cloves

1 1/2 cups Martha's Pink Applesauce

Potato Dumplings, for serving

Season roast generously with salt and pepper. Heat a large Dutch oven or other heavy pot over medium-high heat. Add 3 tablespoons oil; swirl to coat. Sear meat, turning occasionally, until deep brown all over, about 12 minutes. Transfer roast to a plate.
Reduce heat to medium and add onions, garlic, remaining 1 tablespoon oil, and a splash of water. Raise heat to medium-high and cook, stirring frequently, until onions are translucent, about 8 minutes. Stir in sugar, vinegar, wine, thyme, peppercorns, juniper, bay leaves, and cloves. Bring to a boil, then remove from heat and stir in applesauce. Add roast; turn to coat. Let cool 20 minutes, then cover and refrigerate at least 8 hours and up to 24 hours, turning once.
Preheat oven to 300 degrees. Transfer Dutch oven from refrigerator to stove top; turn roast in liquid. Bring mixture to a boil over high heat. Cover; transfer to oven and bake 2 1/2 hours, turning roast every 30 minutes. Uncover and bake until roast is tender and the tip of a knife pierces through easily, about 30 minutes more. Remove roast; transfer to a cutting board to rest.
Meanwhile, cook sauce over high heat until reduced to a silky consistency, 8 to 10 minutes. Taste sauce; add 1 to 2 teaspoons sugar if too acidic.
Cut roast against the grain into thin slices; return to pot. Divide sliced meat with sauce, dumplings, and reserved croutons among plates. Top with thyme and serve.