Proof the yeast. Combine warm milk, 1 tsp of the granulated sugar, and yeast in a small bowl. Stir gently and let sit 5–10 minutes until foamy. If nothing happens after 10 minutes, your yeast is likely expired — start with a fresh packet.
Make the dough. In a large bowl or the bowl of a stand mixer fitted with a dough hook, whisk together flour, remaining sugar, salt, and cardamom. Add the yeast mixture and egg. Mix until a rough dough forms, then add softened butter in small pieces while kneading. Knead for 8–10 minutes until the dough is smooth, elastic, and slightly tacky but not sticky.
First rise. Shape the dough into a ball and place in a lightly greased bowl. Cover with a clean kitchen towel or plastic wrap. Let rise in a warm, draft-free spot for 60 minutes, or until doubled in size.
Make the filling. Beat softened butter, brown sugar, cinnamon, and cardamom together until a smooth, spreadable paste forms. Set aside at room temperature.
Roll out the dough. Punch down the risen dough and turn out onto a lightly floured surface. Roll into a rectangle approximately 16 × 12 inches (40 × 30 cm). Spread the cinnamon filling evenly across the entire surface, all the way to the edges.
Fold and cut. Fold the dough in half lengthwise, bringing the top edge down to meet the bottom. Press gently to seal. Using a sharp knife or bench scraper, cut into strips approximately 1 inch (2.5 cm) wide — you should get 16–18 strips.
Shape the buns. Hold each strip at both ends and twist in opposite directions 3–4 times. Coil the twisted strip around two fingers, overlapping the layers, then tuck the loose end firmly underneath. Place on parchment-lined baking sheets, spacing buns about 2 inches (5 cm) apart.
Second rise. Cover the baking sheets loosely with a kitchen towel. Let the shaped buns rest 30–45 minutes until visibly puffed.
Preheat the oven to 400°F (200°C) conventional, or 375°F (190°C) for fan/convection.
Egg wash and sugar. Brush each bun gently with egg wash. Scatter pearl sugar generously over the tops.
Bake for 12–15 minutes until deep golden brown. Watch closely after the 12-minute mark — they color fast.
Cool and serve. Transfer to a wire rack and rest for at least 10 minutes. Serve warm alongside strong black coffee. Store in an airtight container at room temperature for up to 2 days.
