Preheat oven to 375 degrees.
Bring a large pot of water to a boil, then gently place the sweet potato pieces in the boiling water and cook until very tender. 20-25 minutes.
While the sweet potatoes are cooking., on a parchment-covered sheet pan, place your halved and seeded acorn squash flesh-side down. Drizzle with olive oil and bake for 30 minutes or until tender when a skewer can easily slide into the skin side of the acorn squash.
Once sweet potatoes are fully cooked, drain and mash with the 3 tablespoons of butter and ½ teaspoon sea salt. Taste and adjust salt as needed. Cover and set aside.
Remove the acorn squash from the oven and gently flip it over to be flesh side up. Fill the cavity of the squash with the mashed sweet potato mixture.
Place the filled squash onto a serving dish or platter, top with the toasted crushed pecans, and drizzle with the maple syrup.
They can be served immediately or refrigerated and then reheated in a 350-degree oven for 30 minutes or until hot.