In a large mixing bowl, combine all-purpose flour, granulated sugar, and salt. Create a well and pour in warm milk, melted butter, eggs, and vanilla extract. Stir until a shaggy dough forms and knead for about 5-7 minutes.

Transfer the kneaded dough into a greased bowl, cover with a kitchen towel, and let it rise in a warm area for about 1 hour until doubled in size.

Prepare the filling by mixing brown sugar and ground cinnamon in a small bowl. Set aside to let flavors meld.

Once risen, punch the dough down and roll it into a rectangle about 1/4 inch thick. Brush with melted butter and sprinkle the cinnamon-sugar mixture evenly over the surface.

Starting at one edge, tightly roll the dough into a log and cut it into 12 equal pieces.

Arrange cut rolls on a parchment-lined baking sheet in a triangular shape to resemble a Christmas tree. Cover and let rise for another 30 minutes.

Preheat oven to 350°F (175°C) and bake the rolls for 20-25 minutes until golden brown.

While the rolls are baking, whisk together powdered sugar and milk until smooth. Adjust with more milk for desired consistency.

Drizzle the icing over the cooled rolls and sprinkle with colorful toppings. Serve warm.