(If you don't have a food processor, let butter and cream cheese come to room temperature. With a stand or hand mixer with beater attachment, or just a spoon or whisk, cream together butter, cream cheese and sugar just until light and fluffy, about 1 minute. Then add in sour cream, vanilla and salt and combine. Lastly, add in flour and mix with a spoon or your hands just until combined. This method will lead to a chewier rugelach vs. the flakier cookie with cold ingredients.)

Lightly flour a clean surface and dump dough onto the surface. Divide the dough into four equal sized balls (I use a scale) and flatten each into a disk. Dough should be a little sticky. Wrap each disk in saran wrap and chill for two hours or overnight. It also freezes well for up to 2 months.

When ready to bake, combine chocolate, cocoa powder, sugar, salt and cayenne pepper for filling in a small bowl. Prep your melted and cooled butter.

Whisk egg yolks with 1 teaspoon water to make egg wash.

Brush 1 tablespoon of the melted butter on the rugelach. Sprinkle about 1/4 of filling onto the circle. Cut the circle into 12 even triangles. Roll up each triangle from the wide end and secure the point into the cookie so you have a little spiral. Place cookies on a parchment lined cookie sheet point side down, and freeze for 30 minutes. Repeat with other balls. Whisk egg yolks with water and wash over rugelach and sprinkle with more sugar.