In a small bowl, whisk together the egg and heavy cream to make an egg wash. Set aside.
On a lightly floured surface, roll out the puff pastry to form a 12 1/2-inch by 17 1/2-inch rectangle. Cut 1/2-inch strips from each side of the puff pastry. Transfer puff pastry rectangle to a baking sheet that has been sprinkled with the water. Neatly brush a 1/2-inch wide border of water along each edge of the puff pastry rectangle. Top with corresponding strips of dough, pressing gently with your fingers to adhere. Using a fork or a docker, poke holes in the dough. Let stand at room temperature for 30 minutes. Transfer to refrigerator and chill for 1 hour.
Preheat oven to 400 degrees F.
Sprinkle chilled dough with 2 tablespoons sugar. Arrange plums on dough in overlapping rows. Sprinkle with remaining 1 1/2 tablespoons sugar and dot with butter. Brush edges with egg glaze. Place in oven and bake for 20 minutes. Rotate baking sheet in oven and continue baking until the edges are puffed and golden brown, 20 to 25 minutes more. Serve with ice cream, if desired.
12 1/4 ounces bread flour
5 1/4 ounces pastry flour
17 1/2 ounces unsalted butter
8 3/4 ounces ice water
1/3 ounce salt
Combine in the bowl of an electric mixer the bread and pastry flours, 5 1/4 ounces butter, and water. Using a dough hook, mix ingredients together on low speed for 10 minutes. Add salt and mix for 3 minutes more.
Remove dough from bowl and transfer to work surface. Let rest for 20 minutes. Shape dough into a 6 by 8-inch rectangle, wrap with plastic wrap, and place on a baking sheet. Chill until dough is very cold, about 1 hour.
Place remaining 12 1/4 ounces butter in the bowl of an electric mixer fitted with the paddle attachment and mix until the butter has softened and is the same consistency as the dough.
Remove the dough from the refrigerator and place it on your work surface with the short side facing you. Spread the softened butter over the bottom half of the dough and fold the dough over the butter to enclose.
Turn the dough so that the short side is again facing you. Roll the dough into a 6 by 18-inch rectangle. Fold dough into thirds. Rotate dough 90 degrees (1/4 turn); roll again into a 6 by 18-inch rectangle; fold in thirds. Press 2 fingers into the dough to indicate the completion of 2 turns. Wrap in plastic; chill for about 2 hours.
Repeat the rolling-out process, rotating the dough 90 degrees before beginning. Mark with 4 fingers, signifying the completion of 4 turns. Wrap in plastic; chill for 2 hours.
Remove the dough from refrigerator. Give the dough its final 2 turns by repeating the rolling-out process, again rotating it 90 degrees before rolling it out. The dough is now ready to be used or it may be refrigerated overnight.
Yield: 2 3/4 pounds
Prep Time: 30 minutes
Cook Time: none
Inactive Prep Time: 5 hours 20 minutes
Creme Fraiche Ice Cream:
1 cup sugar
1 cup water
2 (8-ounce) containers creme fraiche
1/4 cup glucose
1 vanilla bean, split lengthwise and seeds scraped
In a small saucepan, bring sugar and water to a boil; remove from heat. Refrigerate for at least 1 hour, or until chilled.
In a large bowl, whisk together creme fraiche, glucose, vanilla bean seed
scrapings (reserve the bean for another use), and salt. Slowly add chilled syrup; stir to combine. Freeze in an ice-cream maker according to manufacturer's instructions.
Yield: about 6 cups
Prep Time: 5 minutes
Cook Time: 10 minutes
Inactive Prep Time: 1 hour plus