Traditional Swedish Saffron Buns (Lussekatter)

First, gently crush the saffron threads with a pinch of the caster sugar using a mortar and pestle. This helps release the saffron's vibrant color and aroma. Pour the tepid milk into a small bowl, stir in the crushed saffron and sugar mixture, and then sprinkle the fast-action yeast over the top. Let it sit for about 5-10 minutes until it becomes slightly frothy.

In a large mixing bowl, combine the strong white flour, the remaining golden caster sugar, and the salt. Make a well in the center and pour in the melted unsalted butter, the Quark cheese, and the frothy saffron-yeast mixture. Mix everything together until it forms a rough, sticky dough.

Turn the dough out onto a lightly floured surface and begin to knead. Work the dough for about 8-10 minutes until it becomes smooth, elastic, and no longer sticks to your hands. This step is key to developing the beautiful texture of the buns.

Place the kneaded dough back into the mixing bowl, cover it with a clean tea towel or plastic wrap, and leave it to rise in a warm, draft-free spot for about 1 hour, or until it has doubled in size.

Once risen, gently punch the dough down to release the air. Divide it into 12 equal pieces. Roll each piece into a long rope, then coil it into the classic 'S' shape, making sure to leave a small gap in the middle. Press a couple of raisins into the center of each 'S' to complete the traditional Lussekatt look.

Arrange the shaped buns on a baking sheet lined with parchment paper, leaving some space between them. Cover them loosely and let them prove for another 30 minutes until they look puffy.

While the buns are proving, preheat your oven to 200°C (400°F). In a small bowl, lightly beat the egg yolk with a tiny splash of water to create an egg wash. Once the buns have finished their second rise, gently brush them with the egg wash.

Bake the buns in the preheated oven for 12-15 minutes, or until they are a deep golden brown and sound hollow when tapped on the bottom. Let them cool slightly on a wire rack before enjoying them warm with a cup of coffee.