Aggressively zest the 3 large lemons directly into a mixing bowl containing the 1 ½ cups of granulated sugar. Use a fork to vigorously mash the zest into the sugar until fragrant and infused. Reserve exactly 3 tablespoons of this lemon-sugar mixture for later use.

Transfer the remaining lemon-sugar to the bowl of an electric stand mixer. Add the softened stick of butter and cream on medium-high speed until pale and fluffy.

Add the 5 egg yolks, ½ cup of fresh lemon juice, and ½ teaspoon of kosher salt, mixing until unified.

Transfer the mixture to a heat-proof glass bowl. Set the bowl over a saucepan of gently simmering water (a double boiler), ensuring the bottom of the bowl does not touch the water.

Whisk continuously over the indirect heat until the curd thickens heavily and coats the back of a spoon, about 10 minutes (or 170°F on a candy thermometer). Remove from heat, cool to room temperature, and chill in the refrigerator until fully set.

Place the halved strawberries into a small bowl. Sprinkle with 1 tablespoon of the reserved lemon-sugar mixture. Stir gently and set aside to osmotically macerate.

In a separate bowl, use a wooden spoon to vigorously beat the mascarpone cheese, sour cream, and vanilla extract until completely smooth, thick, and unified.

Preheat the oven to 400°F. Line a heavy metal baking sheet with parchment paper.

In a small bowl, whisk the buttermilk and egg together until smooth.

In the bowl of a food processor, pulse the flour, baking powder, baking soda, salt, and ½ cup sugar to combine. Drop the chilled cubes of shortening directly over the dry ingredients. Pulse repeatedly until the fat is cut into coarse, craggy crumbs.

With the machine running, slowly pour in the buttermilk mixture until the dough rapidly clumps together. Stop immediately.

Turn the wet, sticky dough out onto a heavily floured surface. Dust the top with flour and gently pat into a ½-inch thick rectangle. Do not overwork the gluten.

Use a floured 3-inch round biscuit cutter to punch straight down (without twisting) to cut out 12 circles, gently reforming scraps as needed. Transfer to the baking sheet.

Bake for 12 to 15 minutes until risen and deeply golden. Stir the remaining 2 tablespoons of reserved lemon-sugar into the 3 tablespoons of melted butter. Brush this hot glaze over the biscuits immediately upon removing them from the oven. Cool completely.

To construct the parfaits, slice a cooled biscuit in half. Crumble one half into the bottom of a heavy crystal or glass parfait vessel.

Layer heavily with the macerated strawberries and their syrupy juices.

Spoon a thick layer of the mascarpone cream directly over the fruit, followed by a massive, generous dollop of the chilled lemon curd.

Repeat the structural layers with the remaining biscuit half, strawberries, cream, and curd. Serve immediately or chill until service.