In a heatproof bowl, combine 2 large eggs, 2 egg yolks, ¾ cup granulated sugar, 1 tablespoon lemon zest, and ½ cup freshly squeezed lemon juice. Whisk until combined. Place over simmering water and cook for 10-20 minutes, whisking constantly, until thickened.

Remove from heat, strain through a fine mesh sieve, and whisk in ½ cup unsalted butter until smooth. Allow to cool to room temperature.

Pour the cooled lemon curd into the pre-baked tart crust, spreading it evenly.

Cover with plastic wrap and refrigerate for several hours to allow the curd to set.

Once chilled, slice into wedges and serve optionally with whipped cream or berries.