In a large mixing bowl (or food processor), combine the softened butter, salt, egg yolk, sugar, and milk. Mix until smooth and creamy.
Sift the flour and gradually add it into the butter-mixture, mixing just until the dough begins to come together in a ball. (If using a food processor: pulse until the dough just forms a ball.)
Turn the dough out onto a lightly floured surface and gently knead for a minute or two until it’s uniform. Flatten into a disk, wrap tightly in plastic wrap, and chill in the fridge for at least 2 hours.
Preheat your oven to 350 °F / 180 °C. Generously butter eight 4-inch tart pans.
On a lightly floured surface, roll the dough out (ideally between two sheets of parchment) to about ¼-inch (≈6 mm) thickness. Cut circles slightly larger than the tart pan rims and gently press the dough into each pan, trimming off any excess.
Line each shell with parchment and fill with baking beans or rice to blind-bake. Prick the dough generously with a fork. Place the pans on a baking sheet and bake for about 30 minutes, until the crusts are lightly golden. Remove from the oven and allow to cool on a wire rack.
In a medium bowl, beat together the cream cheese, lemon juice, and powdered sugar until smooth and creamy.
In a separate bowl, whip the heavy cream with the vanilla extract until soft peaks form. Gently fold the whipped cream into the cream cheese mixture until fully incorporated.
Divide the filling into two (or more) bowls and add a drop of gel food colouring to each to create pastel shades. Mix until uniformly coloured.
Once the tart shells are completely cooled, spoon or pipe the coloured cheesecake filling into each shell, filling almost to the top.
Refrigerate the filled tarts for at least 2 hours to firm up and let the flavors meld.
Just before serving, top each tart with a few mini chocolate eggs or edible flowers for a cheerful Easter touch.