Preheat your oven to 180°C (356°F) and prepare your cake pans by greasing them with butter and dusting with flour.

In a large mixing bowl, combine softened unsalted butter, caster sugar, and light brown sugar. Beat on medium speed for about 4-5 minutes.

Crack in the eggs one at a time, followed by the vanilla extract. Beat on low speed until well combined.

Gradually add all-purpose flour, baking powder, and salt, mixing until just combined.

Divide the batter between prepared cake pans and bake for 25-30 minutes. Allow to cool slightly after baking.

Let the cakes sit in the pans for 10-15 minutes before transferring to wire racks to cool completely.

In a clean mixing bowl, beat the softened butter until fluffy, then mix in the Carnation caramel until smooth.

Place one cooled cake layer on a serving board. Apply a thin crumb coat of frosting before layering with caramel frosting.

Drizzle additional caramel over the cake, letting it cascade down sides. Sprinkle crushed fudge or flaky salt if desired.

Slice the cake and serve with whipped cream or vanilla ice cream.