Preheat oven to 350°F. Line a sheet pan with parchment paper.
Place flour and yogurt in a medium bowl; stir well with a spoon until just combined and then continue to knead dough by hand in the bowl until smooth, about 1 to 2 minutes. If dough is too sticky to knead, add 1 to 2 more tablespoons flour; let dough sit 5 minutes.
Place a large piece of parchment paper on a work surface; sprinkle with a little flour. Place dough on parchment paper; roll dough into a large, thin circle. Place a 10-inch plate upside-down on dough; trace around plate with a knife to cut out a perfect dough circle.
Spread apple butter evenly over dough, all the way to edges; sprinkle with cinnamon. Slice dough into 8 even wedges, like a pizza. Working with one wedge at a time, roll dough tightly from the wide end to the pointy end; place on prepared pan and repeat with remaining dough to form 8 rugelach.
Bake until lightly browned, 15 to 20 minutes.
Meanwhile, to make glaze, in a small bowl, combine sugar and milk until slightly thick. Drizzle glaze over rugelach before serving.
Serving size: 1 rugelach
WW SmartPoints™ without glaze: 3
WW SmartPoints™ with glaze: 4