For the buttercream, leave butter at room temperature. Stir pudding powder, 3 tbsp. sugar and 6 tbsp. milk until smooth. Bring the remaining milk to the boil, stir the pudding powder into the boiling milk, bring to the boil and simmer for 1 minute. Remove from the stove. Immediately pour into a bowl and place foil directly on the pudding surface. Leave to cool at room temperature for 4-5 hours. Butter and pudding must have the same temperature.
Line each tray of a muffin tray (12 trays) with 2 paper baking cups per tray. Beat the eggs, salt, 1 packet of vanillin sugar and 100 g sugar until creamy with the whisks of the hand mixer. Mix flour and baking soda, sieve onto the egg mixture and stir well. Add oil and yoghurt and stir well.
Spread the dough evenly into the troughs and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 20 minutes. Remove from the oven, place on a cake rack and allow to cool.
Peel the chocolate with a peeler and crumble coarsely. Wash, clean and halve the strawberries and put them into a high mixing bowl. Add 1 sachet of vanillin sugar. Finely puree everything with a blender. Whisk butter with the whisks of the hand mixer until thick and creamy white. Mix the pudding briefly with an egg whisk.
Stir the pudding into the whipped butter by the spoonful. Cool briefly. Lift the muffins out of their trays and place them side by side on a work surface. Put 3-4 portions of butter cream in a potato press and press it evenly onto the muffins. Drizzle with strawberry sauce and sprinkle with chocolate. Add the rest of the sauce.