Roll the thawed loaf of bread into a large rectangle about 1/4 to 1/2-inch thick. KEEP THE RASPBERRIES IN THE FREEZER UNTIL READY FOR THIS NEXT STEP. Toss the raspberries with the sugar and cornstarch; sprinkle evenly over the rectangle. Once the berries start to thaw and macerate with the sugar, it gets messy, so be ready to move fast.
Next, tuck as many raspberries as you can into one of the long edges and start rolling towards the center; then stop at the center.
Repeat with the other long edge, tucking lots of berries into it as you roll towards the center. The berries help make the bumps of the heart, so you don't want very many in the middle where it meets (which will create the bottom/point of the heart), you want more in the edge as you roll towards the center.
The next step is to cut the log you just created into 12 equal pieces. I use dental floss and criss cross it to cut and not smash the rolls. You may need a little flour on your floss if it starts sticking to the rolls. Cut the log in half, then each half into half, and then each of those pieces into thirds. Place 6 rolls each into two round cake pans that have been lightly greased.
Point the edges at the bottom so the rolls look like hearts. Cover and let rest for 1 1/2 to 2 hours. The dough won't rise very much because of the frozen berries, but the berries will release a LOT of juices. The raspberry juices will fill most of the bottom of the cake pans.
Bake at 350 degrees Fahrenheit for 25 to 30 minutes until the dough is cooked and the filling is bubbling. Allow rolls to cool slightly, then mix up the glaze ingredients in a food processor or whisk them together in a bowl and mash berries with a fork. Spoon glaze over the edges of the rolls. These Raspberry Rolls are best served warm or heated up slightly. Enjoy!