Arrange the cut acorn squash on two baking sheets lined with parchment paper or a silpat mat. Brush both sides of the cut squash with olive oil. Roast for 20-25 minutes, flipping the squash every 10 minutes, until nearly soft when pierced with a fork.
Meanwhile, whisk together the mirin, brown sugar, grated ginger, sesame oil, tamari sauce, and rice vinegar in a small saucepan. Bring to boil over medium-low heat.
Whisk the water and miso together in a small bowl and add it to the saucepan. Cook for 1 minute longer, whisking until smooth. Remove from heat and set aside.
When the squash is nearly cooked through, brush the sauce over the top of each cut squash.
Place the squash under the broiler for 3-4 minutes, until it just begins to brown.
Transfer to a serving platter and sprinkle the toasted pistachios and sesame seeds over the top.
Notes
Eating the skin is optional - some find it adds the right crunch to contrast the smooth center while others think it's too tough. Either way, I like to keep it on while roasting to help hold its shape, and it's really easy to only eat the soft orange flesh by just scraping it from the skin with a fork.
This nutritional information has been automatically calculated, and as such, may be incomplete or inaccurate. Please reference the specific ingredients you use for the most accurate nutritional information.