For the dough:
In a small bowl or measuring cup, mix the yeast, the warm water and 1 teaspoon of the sugar; set aside to proof, about 5 to 10 minutes. The yeast will expand as it “grows” so use a container to allow for this.
In a large mixing bowl pour the scalded milk over the shortening, mix on low using the heat from the milk to dissolve the shortening. Cool to lukewarm, about 110 to 115 degrees. Slowing stir in 4 cups of the flour, kosher salt, the remaining 1 cup of sugar, the mashed potatoes, eggs, and the dissolved yeast. Add the remaining 3 cups of flour, one cup at a time, mixing well after each addition.
Place the dough in a large bowl that has been lightly greased, turning the dough once to coat. This keeps a film from forming on top of the dough. Cover the bowl with plastic wrap and set the bowl in a warm spot and let the dough rise until doubled, about 45 minutes to 1 hour.
For the filling:
In a small bowl mix together the brown sugar and the cinnamon.
To make the rolls:
Divide the dough into fourths and using a floured rolling pin roll each section of the dough out on a floured surface into a rectangle about 8” x 12” x ¼” thick. (For larger rolls, divide the dough in half and roll each into a rectangle about 16” x 24” x ¼” thick.)
Brush the top of the dough with ¼ of the melted butter, about 2 tablespoons, covering from edge to edge. Spread ¼ of the brown sugar and cinnamon on top of the butter, about ½ cup, using your hands to cover thoroughly and evenly. Don’t skimp on this step.
Then spread ¼ cup of the pecans and ¼ cup currants over the brown sugar and cinnamon.
Starting at the top, lengthwise, roll as tightly and evenly as possible. Once you have the dough in a roll, take a sharp knife and cut into 1” slices. Carefully place rolls into baking pans that have been lightly sprayed with a cooking spray. The rolls should be touching but with a bit of room to rise. Repeat with the remaining dough.
Cover the pans with plastic wrap and let the rolls rise until doubled, about 30 to 40 minutes. Or before rising, you can cover the pans with plastic and refrigerate up to 2 days. When you’re ready to bake, remove the pans and let them warm and rise at room temperature.
Bake at 350-degrees for 20 to 25 minutes or until golden brown on top and bottom. The bread will sound “hollow” when tapped on top. Allow the cinnamon rolls to cool slightly while you make the icing.
For the icing:
In a small bowl, whisk the powdered sugar with the half and half and vanilla until smooth. Drizzle across the cinnamon rolls.