1. Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

2. In a bowl, cream butter and sugar until pale and fluffy. Add eggs one at a time, mixing well, then stir in vanilla.

3. In a separate bowl, sift flour, baking powder, and salt. Add dry ingredients to wet mixture alternately with milk, beginning and ending with flour. Mix until combined.

4. Divide batter evenly into pans. Bake for 28–32 minutes, or until golden and a toothpick comes out clean.

5. Cool in pans for 10 minutes, then transfer cakes to wire racks to cool fully.

6. For frosting: In a saucepan, melt butter and brown sugar, stirring constantly until dissolved. Add milk and bring to a gentle boil for 2–3 minutes. Remove from heat and let cool slightly.

7. Beat in powdered sugar, vanilla, and salt until smooth and spreadable. If frosting is too thick, add a splash of milk.

8. Assemble cake by placing one layer on a serving plate, spreading frosting on top, adding the second layer, then frosting top and sides generously.