Dissolve yeast in warm water. Let the mixture stand for 5 minutes, or until foamy. In a large mixing bowl, combine milk, butter, egg, sugar and salt. Add the yeast mixture and stir well. Add 3 cups of flour, one cup at a time and use a wooden spoon to stir the ingredients together.
Sprinkle just enough of the remaining flour gradually until the mixture turns into a soft dough that gathers in the center of the bowl. Turn the dough over in a generously floured board and knead for 6-8 minutes, adding flour to the surface and to your hands as needed to help with the stickiness, until the dough is smooth and elastic. Shape the dough into a ball and let rise inside a bowl, covered for 1 hour.
Grease two 9-inch round pans. Gently deflate the dough and divide to 50 portions. Flatten each portion in your palms and place a small bit of cream cheese, just enough to fit in the center of the dough. Fold the edges of the dough to cover the cream cheese and twist the ends together to seal. Arrange the balls into the 2 prepared baking pans. Cover them loosely with plastic wrap and let rise for about an hour until puffy and doubled in size.
Preheat oven to 350 F. Bake the buns in the 350 F oven for 18-23 minutes or until the tops are golden.
As the buns bake, make the syrup. Combine sugar and water in a saucepan over medium heat. Let the mixture boil and simmer for three minutes. The syrup should be clear and the sugar has completely dissolved. Turn off heat and add 1/2 tsp of vanilla extract. When the buns are done baking, pour the syrup over the buns, distributing evenly. You may choose not to pour all the syrup. I always find that 1/4 to 1/3 cup remains in my cup. Just make sure to don't skimp on it.