Unwrap phyllo sheets and cover with a damp towel for 10 minutes.

Melt butter in a saucepan over low heat.

Preheat oven to 425°F.

Lightly butter a 14-inch baking pan using a pastry brush.

Lay a phyllo sheet on the pan, re-covering unused phyllo with a damp towel.

Brush the phyllo with melted butter, sprinkle with 1 tablespoon of sugar and 1 teaspoon of Grand Marnier.

Repeat the phyllo, butter, sugar, and Grand Marnier layering process 5 more times.

Arrange sliced apples in a circular mound (6 inches diameter) in the center.

Brush apples with butter and sprinkle with sugar and Grand Marnier.

Stack 6 more phyllo sheets on top of the apples, repeating the butter, sugar, and Grand Marnier layering.

Butter the top (twelfth) phyllo sheet.

Trim off the corners of the phyllo sheets to form an 8-inch round.

Turn up the edges of the phyllo and pinch lightly to seal, creating a rustic look.

Set the pan in the center of the oven and bake until golden, about 30-40 minutes.

If the pastry browns too quickly, cover loosely with aluminum foil.

Serve the tart immediately or reheat gently.

Serve with a dollop of crème fraîche.