Combine yeast, sugar, flour, cardamom, cinnamon and salt in a large mixer bowl.
In a separate bowl or large measuring cup, combine milk, 1 tablespoon oil and butter. Heat to between 120˚ to 130˚F. (Butter may not melt completely.) Add to dry ingredients along with the vanilla and egg yolk; mix until blended.
Turn out onto lightly floured surface and knead until smooth, about 4 to 6 minutes. If dough feels dry, knead in the second tablespoon of oil, a little at a time. Cover and let rest for 10 minutes.
Line two baking sheets with parchment; set aside.
For Filling, combine all ingredients until blended.
Divide dough in half. Knead each half about 5 more folds.
Working with half of the dough at a time, roll out on a lightly floured surface to a 9 X 14-inch rectangle. Spread with half of the filling, leaving a 1/2-inch border around the edges.
Score the center of the long side at the 7-inch mark, being careful not to completely cut through the dough; fold dough in half. Cut dough into twelve 3/4-inch strips across the long edge.
Pick up one strip; twist and lengthen (stretch) the strip slightly. Holding one end between your thumb and index finger, wrap the strip around your three remaining fingers 1 to 1-1/2 times. Slip your thumb out and tuck the end under to create a knotted bun. Place on lined baking sheet. Repeat for remaining strips, then repeat for other half of dough.
Cover buns and let rise until doubled, about 45 minutes.
For Glaze, whisk together egg white and milk.
For Sugar Topping, combine all ingredients until blended.
Brush on glaze; sprinkle with sugar topping. Bake for 6 to 8 minutes in a preheated 425˚F. oven.
Recipe courtesy of Tessa Huff, Pastry Chef && Blogger @ StyleSweetCA