From the Fannie Farmer Baking Book
Whisk 1 ENVELOPE ACTIVE DRY YEAST and 1/4 cup warm water in a small bowl; let stand for 5 minutes. Heat 1 CUP WHOLE MILK in a small saucepan over medium heat until just warm. Combine 1/4 CUP VEGETABLE SHORTENING. 3 TABLESPOONS SUGAR, and 1 1/2 TEASPOONS KOSHER SALT in a large bowl. Add warm milk; whisk to blend, breaking up shortening into small clumps (it may not melt completely). Whisk in yeast mixture and 1 ROOM TEMPERATURE LARGE EGG. Add 3 1/2 CUPS ALL-PURPOSE FLOUR; stir vigorously with a wooden spoon until dough forms. Knead dough with lightly floured hands on a lightly floured surface until smooth, 4-5 minutes. Transfer to a lightly oiled bowl; turn to coat. Cover loosely with plastic wrap. Let stand at room temperature until doubled, about 1 1/2 hours.
Preheat oven to 350. Melt 1/4 CUP UNSALTED BUTTER in a small saucepan. Lightly brush a 13×9 inch baking dish with some melted butter. Punch down dough; divide into 4 equal pieces. Working with 1 piece at a time, roll out on a lightly floured surface into a 12×6 inch rectangle.
Cut lengthwise into three 2 inch wide strips; cut each crosswise into 4×2 inch rectangles. Brush half with melted butter; fold unbuttered side over, allowing a 1/4 inch overhang. Place flat in 1 corner of the dish, folded edge against short side of dish. Add remaining rolls, shingling to form 1 long row. Repeat with remaining dough for 3 or 4 rows. Brush with melted butter, loosely cover with plastic, and chill for 30 minutes or up to 6 hours.
Bake rolls until golden brown and puffed, about 25-35 minutes. Brush with butter; sprinkle with FLAKY SEA SALT. Serve warm.