For the Strawberry Filling:

1. Sprinkle the sugar over the strawberries and let rest for 20-30 minutes to draw out the juices.
2. Strain off some of the juice and collect in a small bowl. Thoroughly blend in the cornstarch until no lumps remain.
3. Heat the strawberries and their juice over medium heat until bubbling. Add the strawberry juice/cornstarch mixture and cook, stirring constantly, until thickened.
4. Let cool and refrigerate until well chilled. **see note

For the dough:

1. Heat the milk to about 110 degrees F. Add the yeast and 2 tablespoons of the sugar. Mix to combine and let rest 5-10 minutes until bubbly and active.
2. In the bowl of a stand mixer, combine the milk, yeast, rest of the sugar, softened butter, eggs and yolks, salt, and 2 cups flour.
3. Using the paddle attachment, mix to combine, then mix on medium speed for 2-3 minutes to start developing the dough.
4. Change to the dough hook, add 2 more cups of flour, and knead at medium speed (adding the remaining 1/4 cup of flour, little by little as needed) until the dough is smooth and no longer sticks to the sides of the bowl. There may still be some sticking to the bottom of the bowl.
5. Form the dough into a ball and place in a large, lightly oiled bowl, cover with plastic wrap, and let rise in a warm place until doubled in size, about 1 1/2 hours. *see note

Roll and fill the dough:

1. Prepare a 13 by 9 inch baking dish. Lightly butter the dish, cut a piece of parchment to fit the bottom of the pan, place it in the pan, and butter the parchment paper.
2. Remove the dough from the bowl and gently press and roll it out into a 19 by 14 inch rectangle.
3. With the long side facing you, spread the Strawberry Filling over the dough, leaving a 1 1/2 inch border at the far side.
4. Roll the dough, beginning with the long edge closest to you. Roll with a gentle lifting motion to lift the roll over the filling, trying to keep it in its place. If you roll to tightly the filling will squish out. As you get to the far end of the roll, pull up the border that does not have any filling on it and pinch it to the rest of the roll to seal the roll and hold in the filling.
5. Cut the roll into 12 equal pieces and put into prepared baking dish. A sharp, serrated knife and a gentle sawing motion when slicing will help retain the filling in its place. After slicing, scoop up the roll gently using the flat side of the knife to help hold the filling in place when transferring the roll to the pan. Any bits that ooze out can be tucked back into the swirls.

If you are rising and baking immediately:

1. Cover the rolls with a piece of plastic wrap and let rise in a warm place until doubled in size, about 1 1/2 hours.
2. When risen, bake on a rack placed in the lower third of a preheated 375 degree F oven until golden brown. This is about 25-30 minutes in my oven. If you check the internal temperature in the center of one of the rolls, it should register about 188 degrees F.

To rise overnight and bake in the morning:

1. Cover the rolls tightly with plastic wrap and put in the refrigerator overnight. They will begin to rise. In the morning, remove the rolls from the refrigerator and set in a warm place to finish rising until they are doubled in size, about 1 - 1/2 hours.
2. When risen, bake on a rack placed in the lower third of a preheated 375 degree F oven until golden brown. This is about 25-30 minutes in my oven. If you check the internal temperature in the center of one of the rolls, it should register about 188 degrees F.