This is the English translation of the recipe from here. There are more pictures showing the process there. I’m posting it here, mainly for myself, for posterity. Looks delicious!
25 g (~1 ½ T) yeast
1 ¼ cups milk , lukewarm
½ cup granulated sugar
1 pinch of salt
½ tsp cardamom seeds, ground
50 g (~3 T) butter , unsalted
4-5 cups flour
about 150 g (2/3 C) almond paste
2-3 tablespoons milk
4/5 cup (1/3 + a scant 1/2 C) heavy cream
WHAT TO DO
1. Crumble the yeast into a bowl. Add milk and stir until the yeast is dissolved. Add eggs , granulated sugar, salt, cardamom, butter and flour, a little at a time. Mix everything together into a smooth dough and knead vigorously for a few minutes. Let the dough rise under a cloth for 50-60 minutes.
2. Lubricate the edge of a springform, about 24 cm (9″) in diameter. Clip on a parchment paper in the bottom and cut away the edges that stand out. Snap up the form again.
3. Knead the dough and shape it into a ball. Press the ball onto the paper-covered bottom. Cut dough into 8 or 12 wedges, depending on how big buns you want. Let the dough rise under a cloth for about 30 minutes. Preheat the oven to 450*F.
4. Brush the dough with beaten egg . Bake in the center of the oven for 20-25 minutes. Let it cool completely in the pan.
5. Cut apart the semla in the joints and cut a lid on each piece. Scoop out a hollow in the lower part of each piece .
6. Mix together the almond and milk into a sticky mass and add a dollop into each hole.
7. Whip the cream and spread it across the bottom. Place the lids. Dust with icing sugar before serving.