Place in the milk in a microwave safe cup or bowl and warm for about 30 seconds until the temp reaches 110° F.
In the bowl of a stand mixer, whisk together the warmed milk, yeast, and sugar. Let stand for about 5 minutes to let the yeast proof - when the top of the mixture is foamy, it's ready.
Once the yeast is ready, add the flour, salt, egg, and 4 Tbsp of butter.
Using the dough hook, mix on low until a dough ball forms and looks smooth but is still slightly sticky; about 8-10 minutes.
Transfer the dough to a lightly oiled bowl, cover, and set in a warm place to rise for 1 hour or until doubled in size.
Preheat the oven to 350° F and coat a 9x13-inch baking pan with non-stick cooking spray. Melt the remaining 4 Tbsp butter in a microwave safe bowl.
Once the dough has doubled, turn out onto a floured work surface and divide into 4 equal pieces. Roll into a rectangle about 12 inches long by 6 inches wide. Brush lightly with melted butter.
Fold the dough in half, lengthwise and cut into 4 more pieces. Brush again lightly with melted butter.
Fold each piece to create a roll shape then place in the prepared baking pan. Repeat with remaining dough pieces.
Brush the tops of the dough rolls with the remaining melted butter and sprinkle with some flaky sea salt, if desired. Cover and let rest for 15 minutes.
Bake at 350° F for 25-30 minutes or until the tops are golden brown. Remove from oven and sprinkle with a little more sea salt.
Let cool for a couple minutes then pull apart and serve!