Heat the milk in the microwave or in a pan on the stove until it is about 95 degrees F. If you stick your finger in it, it should not feel uncomfortable at all. It should feel like a nice warm bath.
In a stand mixer or large bowl, add 2/3 cup sugar, yeast, and salt. Add the warm milk and stir. Wait 5 minutes to make sure you didn't kill your yeast--it should be bubbly. (Much easier to start over now than in 2 hours.)
Add the softened butter and eggs and beat with the paddle attachment (or a spoon).
Add the flour 1 cup at a time.
After it has all come together, beat on medium for 10 minutes with the paddle, or knead with your hands for 10 minutes. You dough should be very soft and shiny; see photo.
Turn your oven on to the warm setting, about 170 degrees F. Grease a large bowl.
Scrape the dough onto a large well-floured work surface. Knead 1-2 times to bring the dough together. Place the dough in a well-greased large bowl and cover with a tea towel.
Turn off your oven, and place the bowl inside. Let the dough rise until doubled, at least an hour and a half, if not 2.
Line a 9x13 inch pan with parchment paper, then spray with nonstick spray. Set aside.
Punch down the dough and roll into an 18x10 inch rectangle on a large well-floured work surface. Spread the dough with about 2 tablespoons of softened butter.
In a small bowl mix together 1/2 cup sugar and 2 teaspoons cornstarch. Sprinkle this mixture over the buttered dough.
Scatter the frozen raspberries over the dough. I pulsed mine in the blender a couple times to break them up a bit, but I've tried it both ways and that step is totally optional.
Carefully roll up the dough, starting from a long end. (Your roll should be about 18 inches long).
Use a sharp knife to cut into 12 rolls. (Cut in half, cut the halves in half, then cut each of those sections into thirds.)
Place the rolls into the prepared 9x13 inch pan. I like to put the end rolls (the wimpy looking ones) in the middle of the pan so they don't get over baked on the edge.
Turn your oven on to the warm setting again, then turn off and place the rolls inside, covered with the same tea towel. Let rise for 1 and 1/2 to 2 hours, or until puffy (see photos).
During the last 15 minutes of rising, remove the rolls from the oven and preheat the oven to 400 degrees F. Cover the rolls with aluminum foil.
Bake the rolls for about 25-30 minutes, or until they are golden on top and the rolls do not jiggle at all when you shake them. You may need to remove the foil for the last few minutes to brown the center rolls.
To make the frosting, beat together the butter and cream cheese until smooth. Add the powdered sugar and beat. Add 3 tablespoons milk, salt, and coconut extract. Beat well. Add more milk until the frosting is the consistency that you want.
When the rolls have cooled long enough to handle, invert the rolls so that the filling doesn't stay on the bottom. Lift the rolls using the parchment paper and flip them into the pan. This is optional and definitely not as pretty as the top, so keep that in mind if you are trying to impress.
Drizzle or spread the rolls with the coconut cream cheese frosting and serve warm.