Preheat oven to 170°Celsius.

Beat butter and castor sugar till soft and creamy. Add eggs, one at a time, beating well after each addition.

In a separate bowl, sift flour, cocoa powder, baking powder and salt 3 times. Fold in the sifted ingredients into the creamed mixture alternately with milk, starting and ending with flour.

Pour the batter into three well greased and floured 6-inches round cake tins. Level the tops and bake the cakes for 40 to 45 minutes or until a skewer inserted in the center of the cakes come out without any wet batter.

While waiting for the cakes to cool down, prepare the ganache. Since it needs time to thicken, place the frosting in the fridge fasten the cooling process.

Once the cakes have cooled down completely, level the tops. Remove the ganache from the fridge. Fill each cake layer with a thin layer of icing and stack all the 3 cake layers on top of one another.

Next, use the remaining ganache to cover the top and sides of the cake. If the ganache is too soft, place the cake in the fridge after covering it. It will be easier to smooth the icing when it is slightly firm.

Smooth the sides and top of the cake with an icing scraper.

Once the cake is fully covered with smooth icing, attach the chocolate buttons and the butterscotch chips. Start with the bottom layer and add the dark compound buttons all around the cake before adding the butterscotch chips in between the buttons. And when adding the chips, poke in the pointed ends into the frosting to make use of the flat bottoms. That way, you will get nice flat round studs all around the cake.

Once the bottom is completed, move to the top edge. Again, start with the dark buttons and then complete with the butterscotch chips.

Next add the numbers 7 & 5 for the 75th birthday. For easy attaching, place the cake in the fridge to allow the ganache to set. It will be easier to attach the fondant numbers when the ganache is set rather than when it is soft.

No special glue is necessary, the fondant will stay well in place on the ganache.

Select a total of 6 strawberries that were as similar as possible in size. Cut each fruit into half. To ensure the fruits were well spaced on the birthday cake top, I started by adding 2 exactly on the opposite of each other (in a 12 o'clock and 6 o'clock position).

Then add another 2, in between the earlier 2 pieces (at 3 o'clock and 9 o'clock position). At this point, you will have 4 halves of the fruits on the cake, each in a quarter position on the cake. Next, add 2 pieces of strawberries in between each quadrant. This way, the fruits will be evenly spaced on the cake top.

For the final touch, add one butterscotch chip each in between each strawberry half on the cake.