Step 1
Whisk flour sugar and salt together in a bowl. Add butter and egg; mix with a fork until crumbly. Work dough with your hands until fully blended. Wrap in plastic wrap and refrigerate about 1 hour.
Step 2
Preheat the oven to 400 degrees F (200 degrees C). Roll dough out to fit a 9-inch pie plate. Place crust in the pie plate and prick with a fork.
Step 3
Bake in the preheated oven for 10 minutes. Remove and let cool.
Step 4
Meanwhile place sliced apples sugar butter water allspice cinnamon and cloves in a large pot; cook over medium heat until apples start to release their juices and are just malleable enough to curve while still holding their shape 4 to 5 minutes. Remove apple slices to a plate reserving cooking juices in the pot.
Step 5
Add diced apples to the cooking juices and bring to a boil. Cook until apples are mushy 5 to 10 minutes.
Step 6
Transfer mushy apples to a medium saucepan. Place walnuts in the bowl of a food processor; process until finely ground. Add nuts to the apples; stir until a paste forms. Add cream; bring to a boil. Remove from heat.
Step 7
Whisk egg thoroughly in a small glass bowl. Add 1 tablespoon of the hot cream mixture whisking vigorously to make sure the egg doesn't curdle. Repeat twice more. Pour egg mixture into the saucepan; mix to incorporate. Allow custard to cool stirring often.
Step 8
Spread cooled custard evenly over the crust. Arrange apple slices on top working from the outer edge to the center in concentric circles overlapping the slices to look like a rose.
Step 9
Bake in the preheated oven until browned about 50 minutes.