Beat butter with vanilla until light and creamy. Add sugar then beat until fluffy. Beat in eggs, one at a time.
Stir in 1/2 the sifted flour with 1/2 the milk. Stir until combined. Add remaining milk and flour. Stir lightly then beat lightly until mixture is smooth.
Spread into a greased tin then bake at 190 degrees C for 20-30 minutes, until a knife inserted into the centre comes out clean.