Make the Tangzhong: In a small pot, combine 1 tablespoon flour and 1/4 cup water. Cook over medium-low heat, whisking constantly, until it thickens into a paste. Set aside.

Prepare the Dough: In a stand mixer, combine 3 1/2 cups flour, 1/2 cup sugar, yeast, and salt. Add the egg, milk, tangzhong, and vanilla extract. Mix until a shaggy dough forms. Gradually add butter one tablespoon at a time, kneading until smooth (about 10-11 minutes).

First Rise: Shape the dough into a ball, place it in a greased bowl, and cover with plastic wrap. Let it rise in a warm place for about 1 hour or until doubled.

Make the Peach Filling: In a saucepan, cook the chopped peaches, 1/4 cup sugar, and lemon juice over medium heat, mashing frequently. Stir in the cornstarch slurry and cook for another minute. Remove from heat and let it cool.

Roll and Assemble: Roll out the dough into an 18x15-inch rectangle. Sprinkle with a cinnamon-sugar mixture, leaving a border. Add the peach filling, then roll the dough up tightly. Slice into 12 rolls.

Second Rise: Place the rolls into a greased baking dish, cover, and let them rise for another hour.

Prepare the Crumb Topping: Combine 1 cup flour, 1/2 cup sugar, melted butter, and cinnamon. Sprinkle over the rolls before baking.

Bake: Preheat the oven to 350°F (175°C). Bake for 30-35 minutes, or until the rolls are golden brown.

Glaze: Drizzle with cream cheese icing and serve warm.