Cake tins should be greased and lined to prevent the sponge from sticking to the sides during cooking. It makes life much easier when it comes to turning the finished cake out of the tin.
-Using a pastry brush, brush the base and sides of the cake tins all over with melted butter or oil.
-Cut circles of baking parchment that are just slightly smaller than the diameter of the cake tins. Press one circle of paper into each of the tins.
Source: https://www.bbc.co.uk