Optional toppings: snipped basil and shaved pecorino cheese or Kalamata olives and feta cheese.
Preheat oven to 350 degrees. Cut squash in half, scoop out the seeds and place upside down on a lightly greased baking sheet. Roast squash until a knife can be inserted with little resistance, approximately 1 hour. Remove squash from oven and let cool enough to be handled. Scoop out flesh into a large platter. (Optional: sprinkle with sea salt and ground pepper.)In a separate bowl combine diced tomatoes and avocados. Toss with balsamic vinegar, minced garlic, olive oil, sea salt and pepper. Top squash with the tomatoes and avocado salsa.