Preheat oven to 350 °F (175 °C). Butter and flour two 8‑inch round cake pans and line with parchment rounds.

In a large bowl whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt until evenly combined.

Stir in eggs, buttermilk, warm water, oil, and vanilla until the batter is smooth and glossy—avoid overmixing.

Divide batter evenly between prepared pans. Bake for 30–40 minutes, until a toothpick inserted into center comes out clean. Let cakes cool completely before slicing

Level and torte each layer if desired (slicing each layer into two thinner ones).

Build: place a cake layer on a stand, spread one-quarter of the caramel sauce over it, then frost with one-quarter of the sweet‑and‑salty frosting. Repeat through all layers.

For top, spread remaining frosting, drizzle with caramel sauce, and garnish with extra crushed chips and pretzels.