How to Make It
Preheat the oven to 425°. Cut a thin slice from the base of each acorn squash and set upright on a baking sheet. Brush the tops with 1 tablespoon of the butter. Wrap the shallots loosely in foil.
Brush the cut sides of the sugar pumpkins with 1 tablespoon of the butter and season with salt and pepper. Set cut side down on another baking sheet.
Roast the sugar pumpkins for about 50 minutes, or until tender; roast the acorn squash and shallots for about 40 minutes, or until the shallots are soft and the pumpkins are golden. Keep the squash warm; let the sugar pumpkins and shallots cool slightly. Squeeze the soft shallots from their skins, coarsely chop the shallots and transfer to a bowl.
Scoop the sugar pumpkins from their skins, add to the shallots and mash with the remaining 2 tablespoons of butter, the cream and the chopped thyme. Season with salt and pepper. Spoon the mixture into the acorn squash, garnish with thyme sprigs and serve warm.