Preheat oven to 350° F.
Peel butternut squash and cut into large chunks.
Line a baking pan with foil drizzled lightly with olive oil.
Toss the squash chunks with the oil and bake until fork tender, approximately 45 minutes.
Once cooked, mash the squash with a potato masher or in a food processor. Combine in a large bowl with sugar, apple butter, eggs, sour cream and vanilla. Whisk in the spices and fold in raisins, if using.
Spread mixture in an oiled 1 ½ quart baking dish. Bake uncovered for 45 minutes, or until the center is no longer jiggly.
In a small bowl, melt the butter and stir in other topping ingredients.
When the casserole is finished cooking, sprinkle the topping ingredients across the top and return to the oven for 5 more minutes.
Remove and serve warm or cold.
