From Joanna Gaines’ Magnolia Table cookbook: "It took me a year of Saturdays to get these biscuits just right. Almost every weekend for months I worked up another batch for Chip and the kids to taste and then wrote down their feedback. Biscuit after biscuit was judged to be too heavy, too light, too flat, too salty, too dry, or just... not right. I don’t entirely know what kept me going back to the mixing bowl, but something inside me was clearly determined to prevail. All those failed batches didn’t discourage me—instead each one spurred me to tweak my formula and try again the next week. Of course it helped that I had a houseful of agreeable taste testers who delivered their criticisms with kindness, and encouraged me to keep at it with the kind of enthusiasm that can only be mustered by people who really love biscuits.
I vividly remember the moment I finally nailed it, when the whole family declared simultaneously, 'This is it.' They have been our family's Saturday-morning breakfast ever since. Among the tricks I worked out along the way are the somewhat unusual addition of eggs and the way they are arranged for baking so that they all touch, both of which contribute to the moisture, lightness, and loft of these biscuits." —Food52
In a large bowl, whisk together the flour, baking powder, and baking soda. Add the butter and use a pastry blender to cut the butter into the flour until the pieces are even and about the size of peas.
Stir in the beaten eggs with a wooden spoon until combined. Stir in 1½ cups buttermilk until the dough comes together into a sticky mass. If it is too dry, add more buttermilk 1 tablespoon at a time, mixing after each addition, until it reaches the correct consistency. Cover the bowl and refrigerate for at least 30 minutes and up to overnight.
Position a rack in the middle of the oven and preheat the oven to 400°F. Line a baking sheet with parchment paper.
Scrape the dough onto a floured work surface. Use your floured hands to press it into a round roughly 14 inches across and about 1/2 inch thick.
Use a floured 2 3/4- inch round cutter to cut out about 20 biscuits. If necessary, collect and pat out the scraps to cut more biscuits.
Transfer the biscuits to the prepared baking sheet, arranging them so that they all are touching. In a small dish, beat together the remaining egg and 1 tablespoon buttermilk. Brush the mixture on the top of the biscuits.
Bake until golden brown, 15 to 20 minutes. Let cool slightly in the pan on a rack.
Biscuits are best the day they are made (and ideally fresh out of the oven!). Serve with strawberry jam or gravy, if desired. Store leftovers in an airtight container at room temperature for up to 2 days.
NOTE: For longer storage, arrange the biscuits about 1/2 inch apart on two parchment-paper-lined baking sheets and freeze until solid. Transfer them to a zip-top plastic bag and freeze for up to 2 weeks. There is no need to thaw them before baking.