Draw a design on paper. (I used a picture of a tiara I saw online as reference to draw one that was easy to make.) Draw it on piece of parchment paper with a felt-tip pen.

Turn the paper over, and tape it around a can. (Stabilize the can by crumbling up a piece of foil underneath it.)

If you add feet to the tiara, you can use them to stabilize it on top of the cake later.

Pipe the chocolate out rather thickly (if the lines are too thin they will break). Clean up the ends of the chocolate lines with a bamboo skewer. You can fix any bits that stray out of the lines with a skewer too.

After piping out half of the tiara, place dragées on it using tweezers. When the weather is cold as it was when I made this (in November), the chocolate hardens rather quickly.

If you turn the side of the can with the chocolate piped on it up before you start piping or putting the dragées on, the chocolate is less likely to drip, and the dragées are easier to put on.

Freeze the tiara can and all. Take the tiara off the can, and store it in a plastic container in the freezer. Handle the tiara at all times with your tweezers.

Example 1: Note: Adjust the size of the tiara to the size of your cake (so that it's well balanced).

Example 2: I made this for my second son's birthday cake. I stuck the paper pattern on the tin I used to bake the cake, and made two tiaras at a time and stuck them on to look like lace.

Example 3: This is a birthday cake I made to order. (The banner says "Happy Birthday".)

Example 4: I made this as a wedding cake for a couple.

This is another birthday cake made for my son the year after the one above. I made the banner a bit more decorative.

Here's another example!

The cake used as a base here is"Chocolate Mousse Cake".

https://cookpad.wasmer.app/us/recipes/155172-chocolate-mousse-cake-for-a-special-day