First, with an electric or stand mixer, whip the butter and cream cheese until smooth.
Next, add flour, salt, powdered sugar, egg yolk, vanilla and almond extracts. Mix until the dough just starts to come together. Be careful not to overwork the dough, and don't worry if there are small bits of butter throughout.
Turn the dough out and separate into two discs and wrap tightly with plastic wrap.
Let the dough chill in the fridge for at least four hours - but I prefer overnight!
When it's time to bake, take your dough out of the refrigerator and let it sit to room temperature.
While the chocolate cinnamon rugelach dough sits, line two baking sheets with parchment paper.
Using a double boiler, or the microwave (in 30 second bursts), melt your chocolate until smooth.
Add in the 1/2 teaspoon cinnamon and mix.
Dust your work space with flour and roll the dough out to a circle about 1/16th of an inch thick.
Spread the filling mixture evenly across the dough, almost reaching the edges. I find that an offset spatula is easiest for this process, and it doesn't tear the dough.
With a pizza cutter, cut the dough in half, then half again. (I love this compact one for baking!) You will now have four pieces, each of which you cut into another four. This gives you a total of 16 pieces of dough.
Shape your dough like a crescent roll, starting from the longest edge.
Once rolled, put the chocolate cinnamon rugelach on the baking sheet and slide them into the fridge for 30 minutes to chill.
When you're ready to bake, preheat your oven to 350 degrees F.
Mix the remaining cinnamon and sugar. Once chilled, brush egg wash over the chocolate cinnamon rugelach and dust on the cinnamon sugar combination.
Bake the chocolate cinnamon rugelach for 15-18 minutes, or until golden brown