Butternut Squash with thyme

3 1/2 pounds butternut squash peeled and cut in 1/4-inch-thick slices (about 6 cups) 1 bunch spinach fresh, washed and stemmed, optional 2 tablespoons butter,[...]

1/4 cup unsalted butter 4 cups thinly sliced onions (about 1 pound) 2 1/2 lbs butternut squash , peeled, seeded, cut into 1/2-inch cubes 1 teaspoon sugar 1/2[...]