Preheat oven to 425 F (220 C). Whisk eggs together in a small bowl. In a heavy-bottomed saucepan on the stove, add water, milk, sugar, salt, and butter and heat until butter is melted. Add sifted flour and stir in completely on stove. Remove from heat.
Scrape mixture into the bowl of a stand mixer. Slowly add whisked eggs with mixer combining – adding only enough of the egg mixture until the dough looks smooth and soft. Spoon or pipe dough onto parchment-lined baking sheet. Whisk egg for egg wash, and brush over dough balls. Bake 23-25 minutes, or until golden.
For the pastry cream, add cream and milk to a double boiler and bring to just before boiling. Remove from heat. Whisk in lemon juice and lemon zest. Beat egg yolks in a saucepan. Add sugar and cornstarch, and continue beating. When milk mixture has cooled somewhat, slowly add to saucepan, continuously whisking to incorporate. Place saucepan on the heat and bring to a boil. Cook until thickened. Remove from heat. Add the butter and whisk to incorporate. Once cooled, fill a piping bag with the lemon pastry cream. Pipe cream into puffs.
For the caramel, add water to a pan. Add sugar and stir until it starts to dissolve. Place on the heat and bring to a boil. Boil until the sugar starts to turn a deep amber colour. Remove from heat. Pick up a puff and dip it into the caramel. Place it on a round platter. Continue with remaining puffs, arranging them in a circle on the platter and then building up into a pyramid, using the caramel on the bottom to stick to each other. With the remaining caramel, take two forks pressed back to back, dip in the caramel and pull out, drawing caramel strands upwards. Drape strands of caramel over puff pyramid, wrapping around the pyramid from top to bottom.
For a topping, drizzle leftover caramel onto parchment paper and let dry to form sugar angel hair.