For the dough:

1. Heat the milk in a small pot until slightly warm (about 110 degrees).
2. Add the milk and the yeast to a bowl attached to a stand mixer with the dough hook attachment. Let the yeast dissolve and activate for about 5 minutes.
3. Add the egg and mix until just combined.
4. Next, mix in the flour, sugar, cardamom, vanilla, and salt. Mix until combined. Finally, mix in the butter a tablespoon at a time. Continue to knead until the dough is thoroughly mixed and the dough has developed enough gluten. 
5. Transfer the dough to an oiled bowl and carefully fold the blueberries into the dough and let rise until it has doubled in size—about 1 hour.

For the assembly:

1. First, stretch out the dough to a rectangle using your hands over a piece of parchment paper. After you have stretched the dough, lay another piece of parchment paper over the dough and roll it out until it's about 1/4 inch thick. 
2. Spread the blueberry jam evenly over the dough.
3. Roll the dough over its self so that it makes a long log, if the dough is giving you trouble, use the parchment paper to lift the dough. With a very sharp knife, cut the dough into 6-8 pieces that are 1 1/2 inches thick.
4. Line a large baking tray with parchment and place the rolls on top, while leaving space for them to rise. Let them rise again for 30 minutes and preheat the oven to 350 degrees.
5. Beat the egg and brush it thoroughly over the risen rolls.
6. Bake for 25 -35 minutes, until the rolls are golden brown.
7. While the rolls are baking, make the glaze. Bring the sugar, water, and cardamom to a light boil. When the rolls are done, brush the syrup over them. For sweeter rolls, do two coats.