Dissolve yeast in the warm water. The water needs to be about 110 degrees otherwise the yeast won't activate. Use a thermometer to make sure it's not too cold or too hot.
Add in the teaspoon of sugar into the yeast mixture. Let it sit for 10 minutes. The mixture should start to foam.
Using a food processor, add in the sugar and 3 cups of bread flour. Pulse 10 - 12 times to combined the dry mixture.
Add the cold, cubed butter into the food processor and turn the processor on high. Let it mix until the flour looks coarse and yellow tinted about 30 seconds. This will cover all the flour with the butter and help make the crust flaky.
Add in the yeast and water mixture, milk, and eggs. Pulse until combined. The dough will be incredibly sticky.
Add in 1 cup of flour and pulse until the dough starts to pull away from the sides of the processor. The dough will still be quite sticky.
Turn the dough out onto a well floured surface. Knead it the remaining cup of flour or enough so the dough isn't sticky anymore. The dough should be very soft.
Spray a bowl with non-stick cooking spray and place the dough in it. Spray the dough with the non-stick cooking spray and cover with a tea towel. Place in a warm place and let the dough rise until doubled. My dough took about 2 hours to double.
Once the dough has doubled, punch it down carefully. Flour the clean work surface again and begin to roll out the dough. Make sure you have a nice rectangle form. I would say I rolled mine out close to 16 inches by 18 inches.
Filling
In a medium bowl, add in the nutella and peanut butter. Mix until completely combined.
Spread all of the nutella and peanut butter mix on the rectangle of dough. Make sure it is evenly spread out. Leave about ½ inch on all edges bare.
Sprinkle the brown sugar on top of the nutella and peanut butter spread.
Begin rolling the dough up starting with the longest side. This way your roll of dough will be longer rather than fatter.
Prepare a 9x13 pan with non-stick cooking spray.
Using a piece of unflavored floss, slide it under the bottom of the dough. Measure about 2 ½ inches from the end and cross the two ends of the floss to cut it. This is the easiest way I've found to do this.
Place each roll in the prepared pan and give it a press down. Cover the rolls and let double again. Mine took another 2 hours to double.
Preheat oven to 350 degrees. Place the pan of rolls in the oven for 35-45 minutes or until they're done. Give one of a rolls that's facing the center of the pan a little tug. If it's still doughy, let it bake for a while longer. Let cool.
Glaze
In a small microwave-safe bowl, add in the grape jam. Place in the microwave for 30 seconds. Stir until the jam is all liquid. Add in the butter and continue mixing until the butter is completely melted.
Let cool for 15-20 minutes or until completely cool.
Add in the powdered sugar and whisk until the powdered sugar is incorporated. It should form a pretty fluid glaze.
Using the whisk, swirl the glaze on the peanut butter and nutella rolls.