Prepare the oven and tins – Preheat the oven to 180°C (350°F). Grease and line two 8-inch cake tins with baking parchment.

Cream butter and sugar – Beat butter and caster sugar together until light and fluffy.

Add eggs gradually – Mix in the eggs one at a time, beating well after each addition.

Add caramel and vanilla – Stir in the caramel sauce and vanilla extract.

Combine dry ingredients – In a separate bowl, sift together self-raising flour and baking powder.

Fold the batter – Gently fold the flour mixture into the wet mixture, adding milk to loosen the batter.

Bake the sponge layers – Divide the batter between the tins and bake for 20–25 minutes, until the cakes spring back when lightly pressed.

Cool the cakes – Leave the cakes to cool completely on a wire rack before frosting.

Prepare the frosting – Beat butter and icing sugar until smooth. Add caramel sauce, cream, and sea salt, then mix until fluffy.

Assemble the cake – Spread frosting over one sponge layer, place the second layer on top, and frost the top evenly.

Finish with caramel drizzle – Drizzle extra caramel sauce over the top of the cake.