TO MAKE THE CHEESE: In a large saucepan, over medium-high heat, combine the yogurt & lemon juice, then bring it to a boil.
Reduce heat to medium or medium-low & boil the mixture until it separates (Time is a total estimate, about 15 minutes).
Pour it into a colander lined with a double layer of cheesecloth & let it drain for several hours.
FOR THE DOUGH: After the cheese has been draining for about 1 hour, start the dough by stirring the yeast into the milk & letting it stand for 10 minutes.
In a large mixing bowl & using a wooden spoon, blend butter & sugar together, then add the flour.
Add yeast milk, orange Juice & olive oil & knead until the dough is smooth, then cover & let rise for 1 hour.
FOR THE FILLING: Meanwile, in a bowl, mix the cheese with the egg & sugar, then set aside.
Preheat oven to 425 degrees F & line 2 large baking sheets with parchment.
When dough is ready, divide it into 2 or 3 pieces & roll out the 1st one to 1/2-inch thickness, then cut out as many disks as you can using a 4-inch biscuit cutter.
With the tips of your fingers, flatten the edge of each disk & fold it in at regular intervals to produce a fluted, slightly raised edge.
Place each fluted disk on the lined baking sheet & flatten the dough a little more inside the edges.
Repeat with the other disks of dough.
Spread 1 1/2 to 2 tablespoons of cheese on each disk, then sprinkle with a little cinnamon & bake for 20-25 minutes or until lightly golden.
Serve at room temperature ~ They are best served the day they're made.