Conchas

Preparation

1. Dough

   Step 1

   Whisk ½ cup lukewarm (about 105°) whole milk, 1 Tbsp. plus 1 tsp. active dry yeast, and 1 Tbsp. (12 g) granulated sugar in the bowl of a stand mixer. Let sit until foamy, about 5 minutes.

   Step 2

   Add 3 large eggs, 4 cups (500 g) bread flour, and remaining 7 Tbsp. (88 g) granulated sugar to bowl with yeast mixture and attach to stand mixer fitted with dough hook. Mix on low speed just until eggs are combined, about 30 seconds. Sprinkle in 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt and mix until a shaggy dough comes together (some loose flour is okay), about 1 minute. Scrape down bowl with a rubber spatula or bowl scraper. Increase speed to medium and, with motor running, beat in zest of 1 navel orange, then add ½ cup (1 stick) chilled unsalted butter, cut into ¼" pieces, a few pieces at a time, incorporating completely before adding more. Continue to mix until dough is smooth and elastic and slaps against sides of bowl, 10–15 minutes. Pinch off a golf-ball-size piece of dough and stretch between your fingers as thin as possible without breaking. If you can see light through the dough, it’s ready. If not, continue mixing 5–10 minutes more and try again. Transfer dough to a work surface.

   Step 3

   Coat inside of stand mixer bowl with nonstick vegetable oil spray and return dough to bowl. Cover with plastic wrap followed by a kitchen towel (this will help create a warm environment) and let sit in a warm, draft-free spot until doubled in volume, about 1½ hours.

   Do ahead: Dough can be made 1 day ahead. Keep covered and chill.

2. Topping and assembly

   Step 4

   While the dough is rising, place mix-in of your choice in a medium bowl if using: ½ cup (16 g) freeze-dried raspberries or strawberries, finely ground, sifted (for pink); ¼ cup pistachio paste or pistachio cream or butter plus ¼ cup (30 g) very finely chopped raw pistachios (for green); or 2 Tbsp. unsweetened cocoa powder (for brown). Add ¾ cup plus 3 Tbsp. (120 g) all-purpose flour, 6 Tbsp. plus 2½ tsp. (85 g) light brown sugar, 2 tsp. vanilla extract, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt. Using a fork, your hands, or a pastry cutter, work in ½ cup (1 stick) unsalted butter, room temperature, cut into 1" pieces. Gather mixture together and knead until the texture of Play-Doh, about 2 minutes. If it feels too wet and sticks to your hands, work in more flour 1 Tbsp. at a time. If it feels crumbly and dry, work in more butter 1 Tbsp. at a time. Gather topping into a ball, wrap in plastic, and set aside.

   Step 5

   Turn out dough onto a work surface and divide into 15 equal pieces (about 65 g each); cover with a kitchen towel. Working with 1 piece at a time, cup your hand over dough and drag across surface in a rapid circular motion to form dough into a tight ball. Do not add flour, as you want friction between the dough and the surface.

   Step 6

   Divide balls between 2 parchment-lined baking sheets, spacing 3" apart. Press each ball with your palm to flatten by about half (dough will start to slowly rise again once your hand is lifted).

   Step 7

   Divide topping into 15 equal pieces (20–27 g each, depending on what mix-in you used). Working with 1 piece at a time, roll pieces into balls. Using a tortilla press lined with plastic wrap, gently flatten balls to about ¼" thick (if you don’t have a press, you can place a piece on a large sheet of plastic, fold plastic over to cover, and press with a pie dish or small skillet to flatten). Whisk 1 large egg yolk and ½ tsp. water in a small bowl to blend. Brush each ball of dough with egg wash. Firmly press topping over surface of each conchas so it completely adheres to top of dough.

   Step 8

   Using a concha cutter or a sharp paring knife, score topping to make curved lines that resemble the surface of a seashell about ¼" apart; be careful not to cut into dough. Cover conchas with kitchen towels and let sit in a warm, draft-free spot until doubled in volume and dough springs back slowly when poked with your finger, 1½–2 hours. (Timing will depend on the temperature. It’s okay if score marks expand and the topping is cracked in places.)

   Step 9

   When conchas are almost done rising, place racks in upper and lower thirds of oven; preheat to 350°.

   Step 10

   Uncover conchas and bake, rotating baking sheets top to bottom and front to back halfway through, until topping is firm to the touch and cracked, and buns are golden brown on the bottom and between cracks in topping, 22–25 minutes. Let cool on baking sheets 10 minutes, then transfer to wire racks. Serve warm or let cool completely.

   Do ahead: Conchas can be baked 3 days ahead. Store airtight at room temperature.