Prepare the Dough:
In a large mixing bowl, combine 1 cup of flour, sugar, yeast, salt, and cinnamon.
In a separate bowl, whisk together the warmed milk, melted butter, eggs, and vanilla extract.
Gradually add the wet ingredients to the dry ingredients, mixing until combined.
Stir in the remaining flour, 1/2 cup at a time, until the dough is soft and slightly sticky.
Knead and Rise:
Turn the dough out onto a lightly floured surface and knead for about 5-7 minutes, or until smooth and elastic.
Place the dough in a greased bowl, cover with a clean cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.
Shape and Bake:
Preheat your oven to 350°F (175°C).
Punch down the risen dough and turn it out onto a floured surface.
Divide the dough into small pieces (about 1-inch balls) and arrange them in a greased bundt pan or a round cake pan.
Cover the pan and let the dough rise for another 30 minutes.
Bake:
Bake in the preheated oven for 25-30 minutes, or until the bread is golden brown and a toothpick inserted into the center comes out clean.
Cinnamon Sugar Coating:
While the bread is baking, mix the granulated sugar and ground cinnamon in a bowl.
Brush the baked bread with the melted butter, then sprinkle generously with the cinnamon sugar mixture.
Cool and Serve:
Let the bread cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Enjoy your Cinnamon Sugar Donut Sweet Bread warm or at room temperature!