In the bowl of a stand mixer fitted with the paddle attachment, combine 1½ cups (188 grams) flour, sugar, yeast, and salt.

In a medium saucepan, heat 1 cup (240 grams) water, sour cream, and melted butter over medium heat until an instant-read thermometer registers 120°F (49°C) to 130°F (54°C). Add warm sour cream mixture to flour mixture, and beat at medium speed until combined. Beat in 1 egg (50 grams) until combined. With mixer on low speed, gradually add 3¼ cups (406 grams) flour, beating just until a shaggy dough forms.

Switch to the dough hook attachment. Beat at medium-low speed until a soft, somewhat sticky dough forms, 7 to 8 minutes, stopping to scrape sides of bowl and dough hook; add up to remaining ¼ cup (31 grams) flour, 1 tablespoon (8 grams) at a time, if dough is too sticky. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size, about 30 minutes.

Line 2 rimmed baking sheets with parchment paper.

Divide dough into 12 portions (about 93 grams each). Shape 1 portion into a round. Place, seam side down, on prepared pan, and flatten into a 3-inch disk. Repeat with remaining dough portions. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size, about 30 minutes.

Preheat oven to 375°F (190°C).

In a small bowl, whisk together remaining 1 egg (50 grams) and remaining 1 tablespoon (15 grams) water; brush onto dough, and sprinkle with sesame seeds.

Bake until golden brown and an instant-read thermometer inserted in center registers 190°F (88°C), 15 to 20 minutes. Let cool on pans for 10 minutes. Remove from pans, and let cool completely on a wire rack. Store in an airtight container for up to 5 days. Tightly wrap in plastic wrap, and freeze for up to 3 months.