Step 1
Preheat oven to 375 degrees F (190 degrees C). Line a baking sheet with parchment paper.
Step 2
Stir 1/2 teaspoon lemon juice into soy milk in a small bowl to make mock buttermilk. Let sit until curdled 5 to 10 minutes.
Step 3
Mix flour 3 tablespoons lemon juice sugar baking powder dill and salt together in a large bowl using a fork. Mix in butter with a pastry blender until dough starts to clump together.
Step 4
Whisk mock buttermilk remaining 2 tablespoons lemon juice and egg together in a bowl. Pour over dough and mix gently with a fork just until incorporated.
Step 5
Dust work surface lightly with flour. Turn out dough and pat into an 8-inch disc. Fold in half and gently flatten back out into a disc. Repeat folding and flattening the dough 3 more times to build fluffy layers in the dough.
Step 6
Transfer disc of dough to the baking sheet and brush with beaten egg. Cut into 8 wedges and pull wedges apart so they are not touching.
Step 7
Bake in the preheated oven until lightly golden about 10 minutes.
Step 8
Remove scones from oven. Combine Parmesan cheese and black pepper together in a small bowl; sprinkle on top of the scones.
Step 9
Return to the oven and bake until golden brown and edges look dry about 10 minutes more.