1/4 lb. Muenster cheese, grated
1/2 lb. Swiss cheese, grated
1/4 lb. mozzarella cheese, grated
2 eggs, lightly beaten
1/2 c. chopped fresh mint leaves or 1 T. dried mint
1/2 c. warm water (105*F to 115*F)
1 envelope active dry yeast
1 T. sugar
6 T. (3/4 stick) butter, melted
1 c. warm milk (110*F to 115*F)
1 T. sugar
1 t. salt
3-3/4 to 4 c. flour
1 egg yolk
For filling: combine all ingredients in a mixing bowl and set aside.
For dough: Combine water, yeast and 1 T. sugar and let stand until foamy, about 10 minutes.
Meanwhile, combine melted butter, warm milk, sugar and salt.
Place 3-1/2 c. of the flour into a large mixing bowl and make a well in the center. Pour the yeast and milk mixture into the well and stir until dough forms. Dust dough with flour as necessary and knead in bowl or on lightly floure board until dough is smooth and pliable but not stiff, about 5 minutes. Roll dough into a circle, 22 to 24 inches in diameter. Butter a 9-inch round cake pan and lay dough in it, letting it spill over the sides. Spoon the cheese filling into the dough and lift edges of dough up and over filling. Join dough in the center and twist for a knot.
Bake at 375*F for 45 minutes. Brush top with egg yolk. Return to oven and bake another 15 minutes until lightly browned.