In a small bowl, combine the melted butter, sugar, syrup, and vanilla extract.
Evenly sprinkle each acorn squash half with salt and pepper.
Using a paring knife, score the insides of the squashes in a hash pattern.
Brush each half with the butter mixture, making sure you cover all exposed surfaces (not the skin).
Evenly spoon the remaining butter mix into the cavity of each half, coating the walls as well.
Bake cut side up on a baking sheet for 1 hour to 1 hour and 15 minutes, or until its flesh is soft and cooked through. It’s hard to overcook squash, but make sure there is sufficient caramelizing and the halves are nicely browned.
Remove from oven, spoon the butter mixture from the bottom of the squash over the flesh.