Custard Strudel

Directions

1. Make the filling: in a medium bowl, rub the sugar, orange zest, lemon zest, and vanilla bean into each other to combine. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and cream cheese until well combined, 1 minute. Add the sugar and mix until light and fluffy, 4 to 5 minutes. Scrape the bowl well.
2. Add the eggs one at a time, mixing well to incorporate each egg before adding the next. Scrape the bowl well before you add the next addition.
3. Add the flour and mix on medium speed to combine. Add the sour cream and vanilla and mix until fully incorporated. Set aside.
4. Assemble the strudel: Line a tabletop with a tablecloth—oilcloth or linen work especially well. A folding card table, kitchen table, island, or any surface you can walk all the way around work especially well (and make stretching easier). Grease a 8x8-inch / 20x20-centimeter baking pan generously with butter.
5. Remove the strudel dough from the refrigerator. Lightly oil your hands. The dough should feel lightly tacky but not sticky, and it should stretch easily. Start by stretching the dough a little like a pizza, trying to keep it rectangular as you work. Once the dough is no longer easy to handle with your hands, lay it down on the covered table.
6. Use the back of your hands (closed fists if you have longer nails) to stretch the dough. Put your hands under the dough at one corner, and gently work your fists outwards, working toward the edge of the table. Continue to do this, bit by bit, working around the dough to slowly stretch it out. The goal is to get it so thin you can see through it (if your tablecloth has a pattern, like stripes or dots,this can be a good guideline). Don’t be alarmed if the dough tears (you’ll be rolling it up, and the tears will be hidden inside ultimately! The dough is very strong, so you should be able to stretch it without major tearing.
7. Once the dough is stretched to the edge of the table, use your fingers to pull gently around the edges to make sure they aren’t too thick.
8. Drizzle the dough with about ¾ of the melted butter (brushing it on may tear the dough, so be gentle if you attempt). Dollop the filling all over the surface, and gently spread the filling to create a fairly even layer (it doesn’t need to be perfect).
9. Working with one of the longersides, gently grab the dough and roll it up into a tight spiral. Use the tablecloth to help you—the less you handle the dough, the less likely you are to rip it as you work.
10. Use scissors to cut any excess dough away from the ends of the strudel. Lift up the rolled strudel and place it into the prepared pan, allowing it to make sort of a squiggly line back and forth inside the pan, filling the whole pan eventually. Keep the seam side down.
11. Preheat the oven to 375°F/`90°C with the oven rack in the center. Brush the exterior of the strudel with the remaining melted butter.
12. In a medium bowl, whisk the eggs, egg yolks, and brown sugar well to combine. Add the milk, cream, vanilla, and salt, mixing well to combine. Gently pour this mixture over the surface of the strudel.
13. Bake until the exterior of the strudel is deeply golden brown, 35 to 40 minutes. Rotate the pan halfway through bake time to help with more even browning. Remove from the oven and cool at least 15 minutes before slicing or scooping into. Serve warm.