Prepare the Dough
In a large mixing bowl, combine flour, sugar, yeast, and salt. Add warm milk, melted butter, and egg. Mix until a dough forms.
Knead the dough on a floured surface for about 8–10 minutes until smooth and elastic. Place the dough in a greased bowl, cover with a towel, and let it rise in a warm place for 1–1.5 hours or until doubled in size.
Prepare the Filling
In a small bowl, mix brown sugar and cinnamon. Set aside.
Roll and Fill the Dough
Once the dough has risen, punch it down and roll it into a 12x18-inch rectangle. Spread the softened butter evenly over the dough. Sprinkle the cinnamon-sugar mixture over the top.
Gently scatter raspberries evenly over the cinnamon-sugar layer, pressing them in lightly.
Roll and Slice
Roll the dough tightly into a log, starting from the long side. Slice the roll into 12 equal pieces and place them into a greased 9x13-inch baking dish.
Bake the Rolls
Preheat your oven to 350°F (175°C). Cover the rolls with a clean towel and let them rise for another 30 minutes.
Once the rolls have puffed up, bake them in the preheated oven for 25–30 minutes or until golden brown and cooked through.
Prepare the Glaze/Frosting
While the rolls are baking, whisk together powdered sugar, milk, and vanilla extract until smooth. Adjust the consistency by adding more milk for a thinner glaze or more powdered sugar for a thicker one.
Serve
Once the rolls have cooled slightly, drizzle the glaze or frosting over the top. Serve warm and enjoy!