(adapted from Bernard Clayton's The Complete Book of Pastry and Slice of Heaven)
For the Shaker Meyer Lemon filling- (yields enough to fill 16 biscuits plus extra to enjoy as you wish. The filling will keep refrigerated for one week.)
(The lemons and sugar need to macerate for at least 3 hours in a non-reactive bowl. I prefer to let them sit in a covered bowl, overnight. )
2 Meyer lemons, sliced paper thin (mine weighed a total of 4½ oz.)
1 cup granulated sugar
2 eggs, beaten
1 tablespoon flour
2 tablespoons butter, melted
Prepare the lemons by slicing them paper-thin, (saving the juice) removing all seeds, and placing the lemon slices and the juice in a bowl with the sugar. Toss gently, cover with plastic wrap and let them sit for at least 4 hours, preferably overnight. (There may be a few stray seeds that should float to the top after the sugar and lemons sit. Remove them.)
In a small bowl, whisk together the butter and flour, then whisk that into the lemon/sugar mixture. Add the eggs, and combine thoroughly. Place the lemon filling in the top of a double boiler, set over simmering water. Cook the lemon filling until it becomes very thick- I take it off the heat when my insta-read thermometer registers 195 degrees. Transfer the filling to a bowl, cover it with plastic wrap and set the bowl over ice to cool completely before filling the biscuits. (You can prepare the lemon filling ahead of time and keep it refrigerated.) When ready to bake the biscuits, pre-heat the oven to 375 degrees.
For the Biscuit dough-
2¾ cups all-purpose flour
1½ teaspoons baking powder
⅛ teaspoon baking soda
1 teaspoon kosher salt
1 tablespoon plus 1½ teaspoons sugar
zest from 1 Meyer lemon
6 oz. cold unsalted butter, cut into pieces
¾ cup cold buttermilk (you may need an additional tablespoon)
egg wash made of one egg yolk plus 2 tablespoons of cream
In the bowl of a standing mixer fitted with the paddle attachment, combine flour, baking powder, baking soda, salt, sugar and zest. Add the butter and mix on low speed until the mixture resembles coarse meal; there should be a few pea-size pieces of butter remaining. Transfer this mixture to a large bowl. Using a rubber scraper, stir in the buttermilk, just until the dough comes together. (If it seems a bit dry, add the additional tablespoon of buttermilk.) Do not overmix. Turn the dough out onto a piece of parchment paper that has been lightly dusted with flour.
Dust your hands with flour and gently pat the dough into a rectangular shape. Use your rolling pin to roll the dough approximately ¼“ thick. Cut out 32 circles of dough. Brush the outside edge of 16 circles with a bit of egg wash. Place a generous teaspoon of cold Meyer lemon filling in the center of each egg washed circle. Top each circle of filled dough with a round of dough, gently sealing the edges together. Place the filled biscuits on a parchment lined baking sheet and brush them with egg wash. Bake on the middle shelf of the pre-heated 375 degree oven for about 20-25 minutes, until golden.