Coat a large bowl with butter and set aside. Combine milk and water in a small saucepan and heat to 100°F to 115°F over low heat. Once mixture is warm transfer to a bowl of a stand mixer and sprinkle yeast over the top. Set aside until mixture bubbles, about 10 to 15 minutes. Add eggs, sugar, and salt and whisk until evenly combined.

Add 3 cups of flour and mix on low speed with the dough hook attachment. Once flour is completely incorporated, turn mixer off and test to see if you need more flour. Dough should be soft, slightly sticky, and not at all dry. If it is so sticky that it is hard to get it off your fingers, add more flour 1/4 cup at a time, until you reach the right consistency.

Increase speed to medium and begin adding butter, piece by piece, letting the first piece disappear into the dough before adding the next, mixing about 10 minutes total.

Transfer dough to prepared bowl and turn to coat in butter. Cover the bowl with plastic wrap and leave in a warm place until dough doubles in size, anywhere from 2 to 4 hours depending of the warmth of your kitchen.

Punch dough down, cover, and let rise again until doubled, another hour or so.

Combine all ingredients in a medium bowl and whisk until smooth. Cover and refrigerate until ready to use.

Grease to 8-inch cake pans and set aside. Transfer dough to a lightly floured work surface and sprinkle with more flour. Roll dough into a 14-x-14-inch square. Spread filling evenly over dough, leaving an inch border around the exterior.

Starting at the edge closest to you, roll dough into a cylindrical shape. You will want to lift the dough up over the filling as you roll to prevent all the filling from gushing out the top. Fold the last 3 inches of dough up over the top to keep the filling from spilling out. Stretch out the final roll to create an even cylinder without bulky spots.

Starting with the end that seems to have the most filling, cut 12 rolls with a sharp knife. If some of the filling squeezes out that's okay, you can gently pushes it into the crevices of the rolls after you put them in the pan.

Place 1 roll in the center of each cake pan. Evenly space 5 rolls around the center roll. Spoon any filling that spilled out back into the rolls. (At this point you can cover the pans with plastic wrap and refrigerate overnight, or place in freezer bags and freeze for up to 1 month.)

If baking immediately, heat oven to 350°F and arrange rack in middle. Set rolls, uncovered, in a warm place to rise for 40 minutes. Bake rolls until puffed and golden brown on top, about 25-35 minutes.

While rolls bake, place frosting ingredients in a stand mixer fitted with the paddle attachment. Start mixer on low then once all ingredients are incorporated increase speed to medium and beat until fluffy.

Remove rolls from oven and let cool slightly. Spread frosting over the top and serve.