Special equipment: A 9-inch fluted tart pan with removable bottom
For the crust: Butter a 9-inch fluted tart pan with a removable bottom. To prepare the crust, add the flour, confectioners' sugar, and salt to the bowl of a food processor fitted with the metal blade and pulse to combine. Add the butter and pulse until the mixture resembles coarse meal. Add the egg yolk and pulse just until the mixture is evenly moistened. Transfer the mixture to the prepared pan and press it into the bottom and sides with a floured measuring cup. Freeze the crust for 15 minutes.
Preheat the oven to 350 degrees F.
Line the cold pastry with parchment paper and fill with pie weights or dried beans. Place the lined tart pan on a baking sheet and bake until set and dry, about 20 minutes. Carefully lift the parchment and the weights to peek underneath and check. Remove the parchment and the weights and continue to bake the crust until light golden brown and crisp, 12 to 14 minutes more. Let the crust cool completely.
For the filling: Preheat the oven to 325 degrees F.
In a large bowl with an electric mixer on medium-high speed, beat the cream cheese, granulated sugar, lemon zest, and salt until light and fluffy, about 3 minutes. Beat in the sour cream. Add the eggs and mix. Scrape the filling into the prepared tart shell and smooth the top.
Bake the tart on a baking sheet until the filling is set around the edges but still has a slight jiggle in the center, 23 to 26 minutes. Transfer to a rack to cool slightly. Wrap loosely with plastic wrap and refrigerate until completely cool, at least 6 hours and up to 2 days.
Dust with confectioners' sugar and top with lemon slices to serve, if you like.
To get the most out of your lemons, invest in a good-quality zester. Use just the outer yellow skin in desserts. If you're using both the juice and the zest, be sure to zest the fruit first. It's much easier that way. Once you've removed the zest, wrap the lemon in plastic wrap for storage. Bald lemons tend to dry out and you want to be able to use that lemon juice another day. If you're just using the juice, try candying the leftover peel.
Recipe courtesy of Samantha Seneviratne