1-Gathering and Mixing Ingredients: In a stand mixer bowl with a dough hook, combine the dry ingredients first: 3.5 cups cake flour, 1 tablespoon instant yeast, and ½ teaspoon salt. This step sets the foundation for a smooth dough. Gradually add the wet ingredients 1 cup whole milk, ½ cup sweetened condensed milk, and 1 medium egg mixing on low speed until it starts to form, which takes about 30 seconds to 1 minute. Scrape the bowl as needed to ensure everything mixes evenly.

2-Incorporating Butter and Kneading: Once the initial mix is ready, increase the speed to medium and add 2 ounces of unsalted butter piece by piece, making sure each piece is fully incorporated before the next. Keep mixing until the dough becomes smooth, elastic, and pulls away from the sides. Transfer it to a lightly floured surface and knead by hand for 1-2 minutes to form a smooth ball.

3-Rising and Shaping the Dough: Place the dough seam side down in a greased bowl, cover it, and let it rise until doubled in size, about 1.5 to 2 hours. After rising, punch down the dough and shape it into a square or rectangle to fit your pan, then roll it tightly into a cylinder, tuck in the sides, and pinch the seam closed. Slice it into equal pieces and arrange them seam side down in a greased baking pan, then cover loosely and let it proof until nearly doubled, about 1 to 1.5 hours.

4-Baking and Finishing: Preheat your oven to 350°F and brush the top with the egg wash made from 1 medium egg and 1 tablespoon whole milk. Bake for 35 to 40 minutes, turning the pan halfway through for even cooking. Right after baking, brush on the condensed milk glaze using 3 tablespoons sweetened condensed milk and 1 tablespoon unsalted butter, softened. Let it cool completely on a wire rack before slicing.