FOR THE SCONES:
Prepare: Preheat oven to 425°F. Line a baking sheet with parchment paper.
Make dough: In a large bowl, using your fingertips or a pastry cutter, work cold butter into self-rising flour until mixture resembles coarse crumbs with some pea-sized pieces. Stir in sugar and lemon zest.
Add liquid: Make a well in center. Add beaten egg and 2/3 cup milk. Using a fork or knife, gently mix until dough just comes together. Add remaining milk if needed - dough should be soft but not sticky.
Shape: Turn onto lightly floured surface. Gently pat (don't roll) to 3/4 to 1-inch thickness. Using a sharp, floured round cutter (2 1/2 inches), cut straight down without twisting. Place scones on baking sheet with sides barely touching.
Bake: Brush tops with beaten egg. Bake 12-15 minutes until golden brown and well-risen. Cool on wire rack.

FOR THE CURD:
Prepare: In a heatproof bowl, combine lemon zest, juice, passion fruit pulp, sugar, and butter. Set bowl over a saucepan of gently simmering water (don't let bowl touch water).
Cook: Stir until butter melts and sugar dissolves. Strain beaten eggs through a fine-mesh sieve directly into the bowl, whisking constantly.
Thicken: Continue whisking constantly for 8-12 minutes until mixture thickens enough to coat the back of a spoon (about 165°F if using a thermometer).
Finish: Remove from heat. Strain through fine-mesh sieve if you prefer smooth curd, or leave unstrained for texture from passion fruit seeds. Press plastic wrap directly onto surface to prevent a skin from forming. Refrigerate until needed.

TO SERVE:
Split scones horizontally and serve warm or at room temperature with generous dollops of lemon passion fruit curd.

STORAGE:
Scones: Best eaten day of baking, store in airtight container
Curd: Refrigerate up to 1 week in clean jars