Why It Works
- A mix of whole wheat and all-purpose flour creates the perfect blend of flavor, crunch, and tenderness.
- Buttermilk moistens the eggless dough, while providing a tangy flavor and lactose for browning, along with enough acidity to activate the baking soda.
- Baking powder helps the biscuits rise without the excess browning and alkaline flavor of baking soda alone.
Like graham crackers, digestive biscuits get their distinctive flavor and tenderness from a portion of whole wheat flour worked into the dough. Their crunchy texture and grainy flavor are perfectly offset by a thick layer of dark or milk chocolate, either of which will be easier to temper if you choose a brand with a high percentage of cocoa butter.
- 4 1/2 ounces all-purpose flour (about 1 cup, spooned; 125g)
- 2 ounces whole wheat flour (about 1/3 cup; 55g), plus more for dusting
- 2 1/4 ounces sugar (about 1/3 cup; 60g)
- 1/4 teaspoon baking powder
- 1/4 teaspoon baking soda
- 1/8 teaspoon (0.5g) Diamond Crystal kosher salt; for table salt, use about half as much by volume or use the same weight
- 4 ounces cold unsalted butter (about 8 tablespoons; 113g), cut into 1/4-inch cubes
- 2 ounces cultured lowfat buttermilk (about 1/4 cup; 55g)
- 9 ounces roughly chopped dark or milk chocolate (about 1 1/2 cups; 285g) (see note)
Make the Dough: Adjust oven rack to lower-middle position and preheat to 350°F (177°C). Combine all-purpose flour, whole wheat flour, sugar, baking powder, baking soda, salt, and cubed butter in the bowl of a food processor. Process until butter virtually disappears into a fine, floury meal. Add buttermilk and pulse to form a damp and crumbly dough. Turn onto an unfloured surface and knead into a ball.
Roll and Bake the Biscuits: On a generously floured surface, roll dough until just shy of 1/4 inch (4.7mm), using as much flour as needed along the way to prevent sticking. Dust away excess flour with a pastry brush and decorate with a docking tool if you like. Cut into 2 3/4–inch rounds and transfer to a parchment-lined half sheet pan. Gather up scraps, knead, roll, and cut as before.
Bake until firm to the touch and light brown all over, about 18 minutes. Cool directly on sheet pan and continue with next step, or store in an airtight container up to 3 days at room temperature.
Temper the Chocolate: Temper chocolate according to one of the methods described here.
Coat the Biscuits: Working with just 2 or 3 biscuits at a time, dollop a generous 1/2 tablespoon, or just over 1/4 ounce, chocolate over each. Spread into an even layer over biscuit and, as chocolate starts to thicken, bounce the tines of a fork across the surface to create a wavy pattern. Repeat with remaining biscuits and chocolate. (Before it hardens, store excess chocolate according to the directions here.) Serve biscuits immediately, preferably with hot tea, and transfer to an airtight container for up to 3 weeks at room temperature.
Food processor fitted with a metal blade, half sheet pan, rolling pin, pastry brush, docking tool (optional), 2 3/4–inch round cutter or wine glass
If you want the most authentic dark chocolate flavor, I've found that Chocolove 70% has a bittersweet intensity almost exactly like the chocolate in the original McVities. For milk chocolate, the caramel notes in Valrhona's Caramelia make it a perfect match.