Preheat oven to 375°F (190°C).

Brush the bottom and sides of the pie crust evenly with beaten egg yolk.

Bake the crust on a baking sheet until light brown, about 5 minutes.

Remove the crust from the oven.

Pour cherry pie filling into the partially baked crust.

In a separate bowl, combine granulated sugar, brown sugar, all-purpose flour, and quick cooking oats.

Mix well.

Add melted butter to the sugar and oat mixture.

Stir until the mixture is crumbly.

Sprinkle the crumbly mixture evenly over the cherry pie filling.

Bake in the preheated oven for approximately 20 minutes, or until the topping is golden brown and the filling is bubbly.

Let cool slightly before serving.