10 ounces fresh shiitake mushrooms, stems removed and reserved, caps halved if small or quartered if large
4 sun-dried tomatoes, not packed in oil (optional)
2 tablespoons olive oil
1 garlic clove, finely chopped
1/2 cup tawny Port, divided
1 large onion, chopped
1 medium butternut squash, peeled, seeded, cut in 1” cubes
1/4 cup pomegranate seeds
Combine shiitake stems, sun-dried tomatoes, if using, and 2 cups boiling water in a medium bowl. Let stand for 15 minutes.
Heat oil in a large heavy skillet over medium-high heat. Add mushroom caps; cook until lightly colored, about 2 minutes. Stir in a pinch of salt; the mushrooms will release some water. Cook until liquid is absorbed, about 5 minutes. Add garlic; stir until fragrant, about 1 minute. Pour in 1/4 cup Port and cook, scraping up any browned bits from bottom of skillet, until all liquid is absorbed, about 3 minutes. Stir in onion and a pinch of salt. Cook, scraping up any browned bits from bottom of skillet, until onion is soft, about 5 minutes. Pour in remaining 1/4 cup Port and cook until sauce is glossy and dry, about 3 minutes.
Add butternut squash; stir to coat. Strain the mushroom stem liquid into skillet; discard stems and tomatoes, if using. Bring liquid to a boil. Reduce heat to medium-low, cover skillet, and cook until squash is almost tender, about 10 minutes. Uncover; continue to cook until liquid is reduced and glossy, 5-8 minutes.
Season with salt and garnish with pomegranate seeds.