Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Grease a baking tray and line with baking paper. Place a baking frame (approx. 25 x 31 cm) on top. Beat butter, fat and both kinds of sugar in a bowl with the whisks of the mixer until creamy. Stir in the eggs one by one, continue stirring for 2-3 minutes. Add buttermilk, oil and 2 tsp. vanilla extract while stirring. Continue beating for 4-6 minutes until the mixture turns white.
Mix flour, baking powder and salt, add to the egg-butter mix while stirring slowly. Briefly stir in 50 g colourful sugar crumbles. Put the dough into the baking frame, smooth it down and sprinkle with the remaining 25 g sugar crumbles.
Bake in a hot oven for 30-35 minutes (after 30 minutes, test with chopsticks). Let the cake cool down on a grid. In a bowl mix 60 ml milk with 1 teaspoon vanilla extract.
Reduce oven temperature (electric cooker: 150 °C/circulating air: 130 °C/gas: see manufacturer). Briefly mix both types of sugar, flour, baking powder, salt and sugar crumbles. Add oil and vanilla extract and knead with the dough hooks of the mixer until crumbles are formed.
Spread the crumbles on a baking tray lined with baking paper. Bake in a hot oven for about 20 minutes. Take out and let cool down.
Whisk butter, fat and cream cheese for 2-3 minutes until creamy. Stir in the glucose and vanilla extract and continue beating for 2-3 minutes until the mixture is shiny white.
Gradually stir in icing sugar, salt, baking powder and citric acid, continue beating at medium speed for 2-3 minutes.