In a large bowl, whisk together 5 cups all-purpose flour, 2 cups bread flour, 1/3 cup granulated sugar, 3/4 teaspoon baking soda, 2 teaspoons kosher salt and 1 tablespoon instant yeast. Set aside.
In a large liquid measuring cup, whisk together 2 1/3 cups milk (warmed to lukewarm), 2 eggs and 1/2 cup vegetable oil. Set aside. Use a tall glass or a large liquid measuring cup to make a well in the center of the dry ingredients (from the 1st step) and add liquid ingredients (from the 2nd step), using a wooden spoon or a rubber spatula to stir until combined. As the dough starts to form, transfer to a lightly floured center and knead for 10 minutes until the dough is smooth and elastic. If the dough is sticking, you can add up to 1/2 cup of extra flour as you knead, but be careful not to overdo it or you'll end up with tough, heavy buns.
Transfer the dough to a greased bowl, cover with plastic wrap and store in a warm place until the dough has doubled in size, about 1 1/2 hours.
As the dough is rising, prepare the filling ingredients. In a small saucepot over medium heat, melt 1/3 cup cubed unsalted butter, constantly whisking. Stir as it bubbles, and after 2 to 3 minutes you should see brown bits appear on the bottom of the pan. Remove from heat immediately and continue to whisk for another 30 seconds. Set aside to cool on a wire rack.
In a medium bowl, combine 3/4 cup granulated sugar and zest from 2 medium oranges by using your fingers to rub the orange zest into the granulated sugar. This will help release oils from the zest and fully infuse the sugar with orange flavor. Set aside.
Once the dough has doubled in size, transfer to a lightly floured counter and use a rolling pin to roll into a rectangle about 16 x 24 inches.
Use a pastry brush to brush the rolled dough with 1/3 cup melted unsalted butter (from the 5th step). Sprinkle the surface of the butter-slathered dough evenly with the sugar and orange mixture (from the 6th step) and 1 teaspoon ground cardamom. Use a hand grater to grate 4 ounces of marzipan over the dough. If the marzipan starts to stick to the grater, allow the marzipan to chill in the freezer for 5 minutes before grating over the dough again. Make sure you sprinkle the sugar, spices and marzipan evenly and completely over the rolled out dough, including the edges.
Working lengthwise, roll the dough into a log, pinching its edges to seal. Cut the roll into 12 pieces, each about 2 inches wide. Place cut sides down on a parchment-lined 18 x 12 inch jelly roll sheet pan, spaced 3/4 inches apart. Cover with plastic wrap and let rise in a warm places until the edges of each roll are rounded and touching, about 1 1/2 to 2 hours.
While the dough is rising, prepare the egg wash by whisking together 1 large egg and 1 teaspoon of honey in a small bowl. Preheat the oven to 350 (F).
Once the rolls have risen, use a pastry brush to brush each roll with the egg wash, until the surface of each roll is completely covered. Sprinkle a generous amount of Swedish pearl sugar over each roll, making sure to use the entire 1/2 cup. Bake the rolls in the preheated oven for around 25 to 30 minutes, or until the edges of each bun are golden in color. Let cool on a wire rack.