Prepare the Dough:

1. In a small saucepan set over medium heat, warm up the milk and butter until the butter is melted and small wisps of steam are just starting to come off the surface of the milk.
2. Pour into bowl of stand mixer fitted with a dough hook. Add yeast and let stand until frothy, about 4-5 minutes.
3. Add sugar, eggs, salt and vanilla extract, and beat until well combined. Working on low speed, add 4 cups of flour, and continue mixing the mixture forms into soft and elastic dough that pulls away from the sides of the bowl, adding more flour as needed if the dough is still too sticky.
4. Shape the dough into a ball and transfer to a lightly oiled large mixing bowl, turning to coat the top with oil. Cover with a clean dishtowel, and let rise in a warm, draft-free spot until doubled in size, about 1 1/2 hours.

Prepare the Filling and Shape the Rolls:

1. In a small mixing bowl, combine melted butter, sugar, ground almonds and orange zest.
2. Punch down dough. Transfer to clean, lightly floured work surface, and roll out to 15×11-inch rectangle.
3. Spread the filling mixture onto the dough, leaving a small border around the edges. Starting with one of the long sides, roll the dough into log, then pinch the seam closed to keep it rolled up. Using a length of dental floss or a sharp knife, cut the dough crosswise into 18 equal slices (each about ½ to ¾ inch wide).
4. Spray three 9-inch round pans with nonstick spray. Arrange the rolls cut-side-up in the pans, spacing them as evenly as possible (don't worry if the rolls look too far apart right now - they'll expand to fill the pan during the next rise).
5. Cover baking dishes with plastic wrap. Let dough rise in warm draft-free area until the buns are doubled in size and have almost filled the pan, about 40 to 45 minutes.

Bake and Frost the Rolls:

1. Preheat oven to 375°F.
2. Bake the rolls in preheated oven for 20-25 minutes, or until tops are golden brown. Remove from oven and let cool in the pan for 10 minutes.
3. While the rolls are cooling, whisk together icing sugar and orange juice to make a thin glaze. Drizzle onto the still-warm rolls, and sprinkle with almonds. Serve right away for best results.