1 acorn squash, cut into cubes and roasted
2 tablespoons extra virgin olive oil
1 tablespoon kosher salt
1 large red onion, chopped
2 tablespoons vegetable oil
5 medium beets (2 lb. without greens), peeled and cut into 1-inch pieces
2 apples, peeled and cut into 1-inch pieces (Honeycrisp, Granny Smith, Gala or Braeburn work well)
3 garlic cloves, minced
4 cups chicken or vegetable stock
4 cups water
3 tablespoons cider vinegar
1½ tablespoons packed light brown sugar
Remove skin from acorn squash and cut into cubes. Place the cubes on a baking sheet and toss with extra virgin olive oil and kosher salt. Bake in the oven at 350° F for 45-60 minutes, until tender. Set aside for use as garnish.
In a 5 to 6 quart stock pot, cook the onion in oil over moderate heat, stirring occasionally, until softened. Add the beets and apple and cook for 5 minutes, stirring occasionally. Add garlic and cook for 30 seconds.
Add the chicken or vegetable stock with 4 cups water and simmer, uncovered, until beets are tender, about 40 minutes. Stir in vinegar and brown sugar.
Puree beet soup using an immersion blender until very smooth. Season with salt and pepper and reheat to desired serving temperature. Use additional water to reduce thickness to desired consistency.
Garnish with cubes of roasted squash.
To Store: Pour into an airtight container and refrigerate for up to one week or freeze for up to 2 months.