• Adjust oven racks to upper-middle and lower-middle positions and heat oven to 200 degrees. Once oven reaches 200 degrees, maintain temperature for 10 minutes, then turn off oven.
• Stir milk, egg, and yeast together in large measuring cup until combined.
• Process flour, sugar, and salt in food processor until combined. Add chilled butter and pulse until mixture looks like coarse cornmeal, about fifteen 1-second pulses. Transfer to large bowl.
• Stir in milk mixture until dough comes together. Turn dough out onto lightly floured work surface. Briefly knead to bring dough together, about 1 minute, adding more flour if necessary. Following steps 1 through 4 below, roll, cut, and assemble biscuits on parchment-lined baking sheets. Cover with kitchen towels and place in warm oven. Let rise until doubled in size, 25 to 35 minutes.
• Remove baking sheets with biscuits from oven and heat oven to 375 degrees; return baking sheets to oven once it is fully preheated. Bake biscuits until golden brown, about 15 minutes, rotating and switching baking sheets halfway through baking time. Serve hot or warm.

How to Assemble Quaker Bonnet Biscuits

• Roll the dough into a 12-inch round.
• Cut out eighteen 2 1/2-inch circles, 3/4 inch thick, and place them on parchment-lined baking sheets.
• Lightly brush larger dough rounds with melted butter.
• Place one smaller round slightly off center on top of each larger round.