Country Rhubarb Cake

Ingredients

• 0.8 teaspoon double-acting baking powder 
• 2 cups cake flour sifted (not self-rising)
• 2 tablespoons powdered sugar 
• 1  eggs separated
• 0.5 cup granulated sugar 
• 1 cup cup heavy whipping cream chilled
• 1 cup brown sugar light packed
• 1 lb rhubarb fresh cut into 1/2-inch pieces (3 cups),
• 0.5 cup butter unsalted cold cut into 1/2-inch cubes
• 0.5 teaspoon vanilla 
• 1 tablespoon irish whiskey (preferably Irish)
• 0.3 cup milk whole

Equipment

• bowl
• oven
• whisk
• blender
• plastic wrap
• hand mixer
• wooden spoon

Directions

1. Put oven rack in middle position and preheat oven to 400°F. Butter a 10-inch glass or ceramic pie plate or a 2 1/2-quart oval gratin dish and chill.
2. Toss rhubarb with brown sugar in a bowl until coated.
3. Whisk together flour, baking powder, and 1/2 cup granulated sugar in a large bowl until combined well. Blend in butter with a pastry blender or your fingertips until mixture resembles coarse meal.
4. Whisk together milk, whole egg, and yolk. Make a well in center of flour mixture and add milk mixture, stirring with a wooden spoon to gradually incorporate flour and form a soft, sticky dough.
5. Transfer half of dough to chilled pie plate and pat out over bottom and halfway up side with well-floured hands, then spoon rhubarb and any juices onto dough. Using a tablespoon, spoon remaining dough in small mounds evenly over top. Lightly beat egg white with a few drops of water, then lightly brush cake with egg wash.
6. Sprinkle remaining 2 tablespoons granulated sugar over top.
7. Bake cake until top crust is golden and rhubarb is tender, 30 to 40 minutes.
8. Transfer to a rack to cool, about 30 minutes.
9. Beat cream with confectioners sugar, whiskey, and vanilla in a bowl with an electric mixer until it forms stiff peaks.
10. Serve cake warm or at room temperature with whiskey cream.
11. Cake can be made 4 hours ahead and cooled completely, then kept, wrapped well in plastic wrap, at room temperature. Reheat if desired.