01 -
Heat oven to 200°C (400°F).
02 -
Heat 3/4 cup apricot jam in a small saucepan over medium-low heat for 2 minutes until it becomes loose and spreadable. Reserve 1/4 cup for the final glaze.
03 -
In a large bowl, combine 1/4 cup granulated sugar, 1/4 cup brown sugar, 2 tablespoons flour, 1 1/2 teaspoons cinnamon, 1 teaspoon lemon juice, and a pinch of kosher salt. Mix until well combined.
04 -
Add the sliced Granny Smith apples to the sugar mixture and toss until apples are evenly coated.
05 -
Lightly flour a clean countertop and roll out the puff pastry sheet into a slightly larger rectangle, approximately 23cm x 34cm (9" x 13.5").
06 -
Transfer the pastry to a parchment-lined baking sheet. Score the crust with a sharp knife about 2.5cm (1 inch) from the edge. Poke the inside area several times with a fork to prevent excessive rising.
07 -
Spread 1/2 cup of the warmed apricot jam across the inner portion of the scored puff pastry.
08 -
Arrange the coated apple slices in a single layer, slightly overlapping them across the pastry surface.
09 -
Fold the edges of the crust over the apples, folding the corners over each other for a rustic appearance. Brush crust with beaten egg and sprinkle with the remaining tablespoon of granulated sugar.
10 -
Distribute the 4 tablespoons of cubed cold butter evenly across the apples.
11 -
Bake for 30-35 minutes until the crust is dark golden brown and the apples are tender but still hold their shape.
12 -
Reheat the reserved 1/4 cup of apricot jam over low heat until loose, then brush over the cooked apples.
13 -
Allow to cool for a few minutes, then slice and serve with vanilla ice cream.