The dough needs to be prepared 24 hours in advance so that it can be properly chilled in the fridge.
In a food processor combine until well blended: butter, cream cheese, yogurt and chopped apricot.
Slowly add in salt, sugar, and flour until somewhat mixed. Remove mixture from food processor and finish mixing dough by hand until well blended. Dough will be solid but soft more like cookie dough. Form dough into a ball, wrap tightly with plastic wrap and refrigerate overnight.
Combine all ingredients in a saucepan on stove top and bring mixture to a rolling boil. Constantly stirring and mashing the mixture until the liquid has reduced to more than half and has begun to thicken. Remove jam from heat and pour mixture into heat-safe bowl and allow to cool. Jam can be made and chilled overnight with the dough, just be sure to bring jam to room temperature before constructing the rugelach. When jam has reached room temp, pour into a food processor to blend walnuts (if desired) to allow for easier spreading.
Preheat oven to 375F.
After 24hrs of chilling, remove dough from fridge and place on a well-floured board. Using a rolling pin, roll dough out into a rectangular shape, roughly 1/4" thick. Spread apricot jam in a light layer across the whole of the dough. Roll dough lengthwise to make a spiraled log shape. Using a pastry cutter or sharp knife, slice the log into 2" square shapes and place shapes on parchment lined baking sheet. Brush squares with egg wash and sprinkle with sugar topping (if desired). Bake rugelach for 25-30 mins at 375F until lightly browned and fluffy. For best taste, allow to cool completely before serving.
Makes approximately 12-15 pieces