Preheat & prep pans: Preheat oven to 350°F. Grease three 8‑inch round cake pans with vegetable shortening, dust with flour, and set aside.

Dry mix: In a medium bowl whisk together flour, butterscotch pudding mix, baking powder, and salt. Set aside.

Cream butter & sugars: Using a stand mixer with paddle attachment, cream softened butter, brown sugar, and granulated sugar until the mixture is light and fluffy.

Add oil & extracts: Mix in vegetable oil, vanilla extract, and rum extract until just combined.

Add eggs: Add eggs one at a time, mixing well after each addition.

Alternate in dry & milk: Add half of the dry ingredient mixture, mix until no dry spots; then pour in milk gradually, mixing; then add the rest of the dry mix until fully incorporated. Scrape bowl sides/bottom to ensure even mixing.

Bake: Divide batter evenly into the three prepared pans. Tap gently to release air bubbles. Bake 22‑25 minutes, or until a toothpick inserted into the center comes out clean.

Cool: Let cakes cool in pans for 10 minutes, then invert onto wire racks to cool completely.

Frosting prep: Cream softened butter in mixer until light & fluffy. Add melted butterscotch chips and beat on medium‑high speed until blended. Gradually add powdered sugar (half first, then the rest), mixing until smooth. Add heavy cream and beat until frosting is light, fluffy, and spreadable (add more cream 1 Tbsp at a time if needed).

Assemble cake: If needed, level the cake layers by trimming domes off with a serrated knife. On a cake plate, place first layer face down, spread ~¾ cup frosting, repeat with second and third layers.

Crumb coat and chill: Apply a thin “crumb coat” of frosting over the whole cake. Refrigerate 10‑15 minutes.

Final coat & optional piping: Frost the outside completely with remaining frosting. If desired, reserve ~¾ cup frosting to pipe decorative edges or design.

Make drip & apply: Melt butterscotch chips with heavy cream in microwave in 30‑second bursts, stirring between, until smooth. Remove cake from refrigerator and immediately spoon drip over top, letting some drip down the sides for effect.

Finish & store: Refrigerate until serving. Store in an airtight container in the fridge for up to three days.