In a medium mixing bowl, whisk together the cake flour, cornstarch, baking powder, and salt. Set aside.

In the bowl of a stand mixer fitted with a paddle attachment or in a large mixing bowl with an electric hand mixer, cream the unsalted butter, powdered sugar, granulated sugar, and vegetable oil until smooth and creamy. Add in the egg and vanilla extract and mix until smooth. Pour in the dry ingredients and mix on low speed until a soft cookie dough forms.

Portion the cookie dough using a large cookie scoop (3 tablespoons) and place on a parchment lined baking sheet. Chill the cookie dough balls for 30 minutes.

While the cookie dough is chilling, preheat the oven to 350℉ (177℃). Line baking sheet pans with silicone baking mats or parchment paper.

Place the chilled cookie dough balls on the prepared baking sheet pan, allowing room for spreading. Bake the cookies for approximately 12 minutes until the cookies puff up in the center and remain pale on the edges. Cool the cookies on the pan for 1 minute and then transfer to a wire rack to cool completely.

In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with an electric hand mixer, cream the unsalted butter for 5 minutes until light and creamy.

Add half of the powdered sugar and mix on the lowest speed setting until fully combined. Add the remaining powdered sugar and continue to mix on low until fully incorporated.

Use a blender or a food processor to grind the freeze-dried strawberries into a fine powder. Then, add in the freeze-dried strawberry powder and mix on low speed until well incorporated.

Add the vanilla extract and salt and mix on low until combined. Slowly drizzle in the heavy cream while mixing on low speed. Scrape the bottom and sides of the bowl occasionally to ensure the frosting is well mixed.

Increase the speed on the mixer to medium and whip the buttercream for about 2 to 3 minutes until it is smooth and creamy. Turn the mixer to low speed and mix the buttercream for several minutes to remove any air bubbles.

In a small mixing bowl, stir together the Golden Oreo cookie crumbs, freeze-dried strawberry powder, and melted unsalted butter until well combined. Set aside.

Fill a piping bag fitted with a Wilton 1A piping tip with the strawberry frosting. Pipe a swirl of the frosting onto the cookies and spread the frosting with an offset spatula. Generously sprinkle the cookies with the strawberry crunch topping.