In a large measuring cup, whisk together milk, butter, egg, and vanilla.
In the bowl of a standing mixer fitted with a dough hook, add 3 cups flour, sugar, yeast, salt, and cinnamon. With the mixer on low speed, add the milk mixture and mix until the dough comes together, about 2 minutes.
Add raisins and increase mixer speed to medium and mix until the dough is smooth and elastic, 9 to 10 minutes. After 5 minutes, the dough should clear the sides of the bowl (have pulled away) but stay attached at the bottom. If the dough is sticking to the sides of the bowl, add the remaining flour, 1 tablespoon at a time, until the dough clears the side of the bowl.
Turn the dough out onto a clean surface and shape into a ball. Coat a large bowl with nonstick spray. Place the dough in the bowl, turning once to cover evenly in nonstick spray, then cover tightly with plastic wrap. Place in a warm, draft-free area to rise until doubled in volume, about 2 hours.
Coat a 9-inch x 13-inch baking dish with nonstick spray or line with parchment paper. Turn the risen dough out onto a lightly floured surface and divide into 12 equal pieces. Shape each piece into a tightly formed bun and place in the prepared baking dish, seam side down.
Cover the buns with plastic wrap coated with nonstick spray. Place in a warm, draft-free area to rise until doubled in volume and touching, about 1-2 hours.
Whisk cream cheese and powdered sugar together in a small bowl until completely smooth. Gradually whisk in milk and vanilla, then add flour and salt and stir smooth. Spoon mixture into a piping bag fitted with a small round tip and pipe crosses over the buns.
Heat oven to 375 degrees. When oven is ready, place tray inside and bake for 12 to 15 minutes until starting to turn golden brown on tops.
While buns are in the oven combine the ingredients for the glaze in a very small saucepan and place over medium heat. Stir constantly until it just barely boils and sugar is dissolved, then remove from heat. Remove buns from oven and brush with the glaze then return to oven for 3 to 4 minutes longer to finish browning. Once they are golden, remove tray from oven again and brush for a second time with glaze and allow them to cool fully before piping on the cream cheese frosting.