Preheat the oven to 350 degrees F (175 degrees C). Coat 2 (8-inch) round cake pans with baking spray with flour and line bottoms with parchment.

To make the cake: Whisk flour, gelatin, baking powder, salt, and baking soda together in a bowl.

Beat butter at medium speed until creamy, 2 to 3 minutes in the bowl of a stand mixer fitted with the paddle attachment. Gradually add sugar, beating until light and fluffy, about 3 minutes. Add eggs, 1 at a time, beating on low speed and scraping down sides of bowl as needed, until just combined. Beat in vanilla.

Add flour mixture in 3 additions alternately with buttermilk, beginning and ending with flour mixture and beating on low speed just until combined after each addition. Divide batter evenly between prepared pans.

Bake in the preheated oven until a wooden pick inserted in center comes out clean, about 40 minutes.

Cool in pans on a wire rack for 10 minutes; remove cakes from pans and cool completely on a wire rack, 1 to 1 ½ hours.

To make the frosting: Add butter and salt to the bowl of a stand mixer fitted with the paddle attachment. Beat on medium speed until creamy, about 3 minutes. Beat in vanilla.

Gradually add powdered sugar, alternately with cream, beating on low speed until completely incorporated and smooth. Increase mixer speed to medium-high and beat until smooth and fluffy, 2 to 3 minutes.

To make the crumble mixture: Place cookies, strawberries, and salt in a food processor and pulse until slightly chunky (bits of strawberry and cookie should still be visible), about 12 pulses. Drizzle in butter and pulse about 5 times to combine.

Trim tops of cakes with a serrated knife if needed to make flat on top.

Place 1 cake layer on serving platter; spread evenly with 1 cup frosting. Top with remaining cake layer.

Spread top and sides of cake with the remaining frosting.

Sprinkle crumble mixture over top and sides of cake, pressing lightly to adhere until completely covered. Chill cake for 1 hour before slicing.