In a small saucepan over medium heat, melt the butter and then add the milk. Heat until "finger warm", about 110° F (or the temperature called for on your yeast packet).
For active yeast: Add a few tablespoons of the milk and butter mixture to a small bowl. Sprinkle the yeast on top and let sit for 5 minutes or until bubbles start to form.For instant yeast: Add yeast directly to flour and mix as per instructions below. In a large bowl, whisk together one egg and the sugar. Pour in the yeast mixture, the rest of the milk and butter mixture, the flour, cardamom, baking powder, and salt. Use a wooden spoon to combine the mixture and then transfer it to a lightly floured surface and knead with hands until smooth, about 3 minutes. The dough should be a little "wet", but if too sticky, add a little more flour, 1 tablespoon at a time.
Place the kneaded dough back in the bowl and cover with a clean tea towel. Let rise in a warm, draft-free area for about 45 minutes.
Meanwhile, line two baking sheets with parchment paper.
When the dough has risen, transfer to a lightly floured surface and divide into 15-16 pieces. (Note: You could also make 10 larger ones or 20 smaller ones.) Form each into a ball and place it onto the baking sheet. Cover with the tea town and let rise for another 30 minutes.
Meanwhile, preheat the oven to 400° F.
In a small bowl, whisk the second egg. When the buns have finished rising, brush the top of each with the egg mixture and then bake in the oven for 10-15 minutes, or until golden colored. Remove and let cool on a wire rack covered with a tea towel.
Once cooled you are ready for part 2, adding the filling and finishing touches! Important: If you don't plan to eat all the semlor right away, only make as many as you will eat. The rest you can put in an airtight bag freeze until you are ready to assemble and enjoy more semlor!