Clear Lemon Meringue Pie Exists, and My Brain Hurts Just Looking at It

For the crust

• 1 1/2 cups plain flour
• 2 tablespoons powder sugar
• 1/2 teaspoon salt
• 1 cup butter, chilled
• 1 medium egg, beaten
• 1/2 cup water, chilled
• Egg wash

For the filling

• 2 sachets (about 2 1/2 teaspoons each) gelatin powder
• 1 1/2 cups caster sugar
• 2 1/2 cups water
• 1 tablespoon citric acid
• 1 teaspoon lemon extract

For the meringue

• 1 cup caster sugar
• 7 tablespoons water
• 4 fresh egg whites, room temperature
• 1/2 teaspoon lemon juice