Dark Chocolate and Royal Icing Muffins

I made this muffin recipe for my guests that I will host at Sugar Feast before. But this time I wanted to add a different interpretation. That's why I didn't add baking powder to it.
Since it did not rise, it was a very dense dough, but it had a unique flavor. Now here are the muffins that are not particularly fluffy and garnished with royal icing.
This recipe is my first attempt at royal icing, frankly, I'm not much of a dark chocolate lover, but I was amazed by the elegance of white royal icing and dark chocolate.
previous Cocoa Dark Chocolate Muffin You can find the recipe here. love..

3 eggs
1 glasses of yoghurt
1 tea cup oil
1 cups sugar
4 soup spoons of cocoa
1 tablespoon of coffee
flour
broken chocolate chips

For Royal Icing:

1 egg white
2-3 drops of lemon juice
1-1,5 cups of powdered sugar

Fabrication:

Beat the eggs and sugar with a mixer until frothy. Add the oil and yogurt and continue whisking. Sift the flour, cocoa and coffee into the egg mixture.
Place muffin paper molds in muffin molds. Fill paper cups halfway or slightly with the muffin batter. Bake in a preheated oven at 180 degrees.

To make Royal Icing: Take the egg white in a deep bowl, add powdered sugar and lemon juice until it becomes snowy (beat for about 10 minutes). You can add more powdered sugar to thicken the consistency.

After the muffins have cooled, take them out of the tray and pour the royal drink on them with the help of a tablespoon. Stick the chopped chocolates in the middle of the cake and serve when the Royal icing dries.