Melt the butter in a pot. Add the milk and heat until lukewarm.
Crumble the yeast in a bowl. Add the milk and butter mixture. Stir until the yeast is completely resolved.
Add agave syrup, salt, cardamom, and the flour. Knead the dough until firm and glossy. Cover the bowl with a clean tea towel. Let it rise for 40 minutes.
Roll the dough and cut into 12 slices. Shape them into balls. Place them on a fitted baking tray. Cover with a tea towel and let them rise for another 40 minutes. Set the oven to 200C/fan.
Bake in the middle of the oven for 7 minutes. This can vary depending on your oven. So keep an eye on the buns first time you make them. They should be slightly golden brown on top when ready. Take them out and let them cool completely.