The Bottom Less Pit

Nut filling
In a high powered blender, blend the nuts into the size of course sand.
In a medium bowl, stir together the ground nuts and the remaining filling ingredients.
Cover the bowl and set aside.

Dough
Whisk the two eggs together until fully mixed, whisk in the sour cream or yoghurt, the milk, and the vanilla extract.
Add the flour, sugar, baking powder, and yeast to a the bowl of a stand mixer and whisk together.
Add the softened butter and egg mixture.
Using the dough hook, knead together on low speed.
The dough should come together into a smooth ball and not be sticky. You should also be able to stretch it at least a few inches without it snapping.
Shape the dough into a ball, lightly grease the mixing bowl, and place the dough back in the bowl.
Cover the bowl and set in a warm place for 45 min.
Pre-heat the oven to 350 F.

Assemble
Line a baking sheet with a silicone baking mat/parchment paper
After 45 min, roll the dough out on a floured surface to 11" x 18".
Spread the nut filling out onto the rolled dough.
Leave a 1/2" border on two long sides and on one short side. Leave 1 1/2" border on the remaining short side.
Start rolling the dough from the short end with only a 1/2" border. Roll once, then fold in the long sides, about 1/2", to keep the filling from spilling out.
Continue rolling until you reach the end, being careful not to push out the filling.
Wrap the roll in parchment paper and leave a 2" gap between the paper and the roll. Leave the ends open.
Carefully lift the roll and place it, seam side down, on the baking sheet.

Bake
Bake the strudel for 30 min.
Remove the parchment paper and bake for another 15-20 minutes.

Final Steps
While the strudel is still warm, brush the strudel with the melted butter. Then liberally dust with powdered sugar until the sugar stops disappearing (dissolving).
Let it cool fully before slicing.