1. Set the oven at 180 degrees.
2. Place 12 muffin cups in a muffin baking tray.
3. Melt the butter without browning.
4. Whisk eggs, sugar and vanilla sugar together in a bowl until light and foamy. Now stir butter and sour milk into the eggnog.
5. Combine flour with poppy seeds, almond flour, baking powder and finely grated peel of the lemon in a bowl. Save the lemon. Mix well and turn with the rest of the dough.
6. Put the dough into the molds and bake for about 15 minutes. Take out and cool completely.
7. Stir in cream cheese and icing sugar together and stir steady with a few drops of lemon juice at a time.
8. Decorate the muffins with frosting and small chocolate Easter eggs.
Make the frosting
1. In a bowl of your stand mixer, or with a hand mixer, beat the cream cheese until smooth.
2. Add the vanilla and powdered suger and beat until smooth.
3. Using th whisk attachment, gradually add the double cream and whip until the frosting is thick enough to pipe. Add more sugar or cream as needed to get the right consistency.