In stand mixer bowl, add 1 cup flour, yeast, sugar and salt; mix well. In saucepan or microwave-safe dish, heat milk to 120-130°F. Add warm milk and butter to flour mixture. Using a paddle attachment, blend on low speed for 30 seconds; beat on medium speed for 4 minutes. Add egg yolks; beat 1 minute.
Switch to dough hook attachment. Gradually stir in enough remaining flour to make a firm dough. Knead until smooth and elastic, about 5 to 7 minutes.(NOTE: For hand mixing: following above steps, mix ingredients in large mixing bowl using a wooden spoon or dough whisk. Knead on floured surface until smooth and elastic.) Place dough in lightly oiled bowl and turn to grease top. Cover; let rise until indentation remains after poking dough with finger down to second knuckle, about 1 hour.
Divide dough into 2 equal parts. Refrigerate half of dough until ready to use. On lightly floured surface, roll the other half into a 12x9-inch rectangle. Brush with half of melted butter. Sprinkle evenly with half of the filling's sugar and coconut. Starting with longer side, roll up tightly. Pinch edge to seal. Cut into 12 slices. Place on greased cookie sheet. Repeat directions with remaining half of dough. Cover rolls with plastic wrap; let rise until indentation remains after lightly touching with fingertip.
Preheat oven to 350°F.
Bake for 20 to 25 minutes. Remove from cookie sheets; place on wire racks with parchment paper underneath (to catch glaze).
Prepare powdered sugar glaze: Combine all ingredients in small mixing bowl; beat until smooth. Drizzle over rolls; serve warm.