Preheat oven to 350 degrees Fahrenheit.

Grease or line a 10- x 15-inch jelly roll pan with Gefen Parchment Paper.

In a large mixing bowl, combine flour and salt. Add in chunks of margarine and combine. Mixture should have a crumbly texture.

In a small bowl, combine egg yolk and parve milk. Add to flour mixture and mix until fully incorporated and dough is smooth.

Spread dough over the bottom of prepared pan.

In a large mixing bowl (you can use the same bowl), toss sliced apples with sugar and cinnamon until fully coated.

Spread apples over dough layer.

In a large mixing bowl (you can use the same bowl again), combine all Crumb Topping ingredients to form a streusel consistency.

Add crumb topping to cover apples in baking pan.

Bake for 25 minutes. Let cool.

Cut into squares and sprinkle with confectioner’s sugar.

Serve either as a side dish, or as dessert. Squares can be served at room temperature, or warm with a scoop of ice cream on top.