In a medium saucepan, combine diced fresh peaches, granulated sugar, and lemon juice over medium heat. Mash peaches gently until bubbly and thickened, about 10-15 minutes.

In a small bowl, mix cornstarch with a bit of water, then stir into the bubbling mixture to thicken. Remove from heat and allow to cool.

In a small pot, whisk together equal parts water and bread flour over medium heat until it thickens to a paste-like consistency, about 2-3 minutes. Let cool.

In a large mixing bowl, combine bread flour, sugar, instant yeast, and fine sea salt.

Pour in the whole milk, heavy cream, large egg, and cooled tangzhong. Knead by hand or with a stand mixer until smooth and elastic, about 5-7 minutes.

Gradually incorporate unsalted butter, allowing the dough to become cohesive.

Shape the dough into a ball and place it in a greased bowl. Cover and let it rise in a warm area for about 30 minutes, until doubled in size.

Roll dough into a rectangle (12x18 inches). Spread cinnamon sugar mixture, followed by peach jam and sliced peaches. Roll tightly and slice into 1-inch pieces.

Place rolls in a lined baking pan.

Cover rolls and let them rise until doubled, about 1-2 hours. Preheat oven to 325°F (162°C).

In a bowl, mix all-purpose flour, sugar, ground cinnamon, and melted butter until crumbly.

After the final rise, sprinkle crumb topping over the rolls. Bake for 30-40 minutes until golden brown.

In a bowl, blend cream cheese, softened butter, powdered sugar, and heavy cream until smooth.

Allow rolls to cool slightly on a wire rack. Drizzle icing over warm rolls.