How to Make It
Prepare the Cinnamon Rolls: Whisk together flour, salt, and 1/2 teaspoon of the cinnamon in a large bowl. Combine milk, yeast, and 1 tablespoon of the granulated sugar in the bowl of a heavy-duty electric stand mixer fitted with paddle attachment; let stand until foamy, about 5 minutes. Add eggs, vanilla, and remaining 5 tablespoons granulated sugar; beat on medium speed until combined, about 1 minute. Add 1 cup of the flour mixture; beat until smooth, about 2 minutes. Change paddle attachment to dough hook attachment. Add remaining flour mixture, and beat on low speed until dough is smooth, about 8 minutes. Add softened butter, 1 tablespoon at a time, beating well after each addition, stopping to scrape sides of bowl as necessary.
Turn dough out onto a lightly floured surface. (Dough will be slightly sticky.) Knead until smooth and elastic, 2 to 3 minutes, using as little extra flour as possible. Shape dough into a ball. Place dough in a lightly greased large bowl, turning to coat all sides of dough with cooking spray. Cover bowl with plastic wrap, and place in a warm (85°F) place, free from drafts, until doubled in size, about 1 hour.
Turn dough out onto a lightly floured surface. Gently roll (trying not to deflate dough) into a 16- x 12-inch rectangle. Brush melted butter over surface of dough. Combine brown sugar and remaining 1 tablespoon cinnamon; sprinkle evenly over dough. Sprinkle cake crumbs over dough, if desired. Roll dough tightly into a log, starting with 1 long side. Pinch seam closed. (Do not seal ends of log.) Using a very sharp or serrated knife, cut log into 12 equal slices. Arrange slices in a lightly greased 13- x 9-inch baking pan. Cover with plastic wrap; let rise in a warm (85°F) place, free from drafts, until doubled in size, about 1 hour.
Preheat oven to 350°F. Remove plastic wrap from pan. Bake in preheated oven until golden brown and a wooden pick inserted in center of 1 roll comes out clean, 25 to 28 minutes. Cool in pan about 10 minutes; remove rolls to serving platter.
Prepare the Icing: Combine cream cheese and butter in a mixing bowl; beat with an electric mixer on low speed until smooth, about 2 minutes. Beat in vanilla. Add powdered sugar; beat on low speed until smooth, about 3 minutes. Add milk, 1 tablespoon at a time, beating on low speed until spreadable consistency is reached. Spread Icing over warm rolls. Serve rolls warm or at room temperature.