Heat the oven to 425°F/220°C.

Peel the sweet potatoes and slice into ½-inch rounds. Arrange in an even layer in a casserole dish.

Melt the butter in a saucepan over medium heat and cook until browned and fragrant, 3 to 4 minutes. Add the brown sugar and maple syrup and stir until dissolved.

Stir in the vanilla, lemon juice, salt, cinnamon, and nutmeg. Simmer gently for 2 to 3 minutes, then add the heavy cream and cook 1 minute more.

Pour the glaze over the sweet potatoes. Cover tightly with foil and bake until tender, 30 to 40 minutes.

Uncover, spoon some glaze from the bottom over the top, and serve warm.