Activate the yeast. Warm the milk to body temperature (about 37 °C). Crumble in the fresh yeast (or sprinkle dry yeast over) and stir in one tablespoon of the sugar. Let it sit for 5–10 minutes until the yeast foams.
Make the dough. In a large bowl combine the activated yeast mixture with the remaining sugar, ground cardamom, salt and melted butter. Gradually add flour while mixing until a soft dough forms. Tip onto a floured surface and knead for 5–7 minutes until smooth and elastic. The dough should be slightly tacky but not sticky; add extra flour sparingly.
First rise. Place the dough in a lightly oiled bowl, cover with a clean cloth or plastic wrap, and let rise in a warm place until doubled in size (about 45–60 minutes).
Prepare the filling. Beat the softened butter with sugar and cinnamon until smooth. You can add a pinch of cardamom or a tablespoon of almond paste for extra flavour.
Shape the buns. Turn the risen dough out onto a lightly floured surface and roll it into a rectangle about 0.5 cm (¼ inch) thick. Spread the filling evenly over the dough. For classic spirals, roll the dough up tightly from the long side into a log and cut into 20 slices. For korvapuusti‑style ear buns, roll into a log, slice pieces on the diagonal and pinch each slice in the middle. For knotted buns, cut the dough into strips, twist and knot them.
Second rise. Place the shaped buns on a lined baking sheet or in paper baking cups, leaving space between each. Cover loosely and let rise again for 30 minutes.
Bake. Preheat the oven to 200 °C (392 °F). Brush the buns with beaten egg and sprinkle generously with pearl sugar or chopped almonds. Bake on the middle rack for 8–12 minutes, until golden brown. Remove from the oven and, if desired, brush lightly with simple syrup for a shiny finish.
Cool and serve. Let the kanelbullar cool on a wire rack. Enjoy warm with coffee as part of your fika. Leftovers can be frozen and briefly warmed in the oven to regain their softness.
