Combine warm milk, yeast, and a pinch of sugar in a large bowl. Let it foam for 5 minutes. Mix in melted butter, egg, remaining sugar, and salt. Gradually add flour until a soft dough forms. Knead for 8 minutes until smooth and elastic.

Place dough in a greased bowl, cover with a damp towel, and let rise in a warm spot for 1 hour until doubled in size.

While dough rises, toss diced peaches with cornstarch and granulated sugar.

Roll dough into a 12x15-inch rectangle on a floured surface. Spread softened butter evenly, leaving a ½-inch border. Sprinkle with brown sugar and cinnamon, then distribute peach mixture over the surface. Roll tightly from the long side, pinching the seam closed.

Using dental floss or a sharp knife, cut into 12 even rolls. Place in a greased 9x13-inch baking dish, leaving space between each roll for expansion.

Let rolls rise for 20 minutes while preheating oven to 350°F. Bake for 22-25 minutes until golden brown and internal temperature reaches 190°F.

Whisk together powdered sugar, milk, and vanilla while rolls cool slightly. Drizzle glaze over warm rolls.