Combine the sugar, Meyer lemon zest, and grated ginger into a bowl. Rub the mix between your hands to release the oils of the zest and the liquid of the ginger. The mixture will be like wet sand.
Add the eggs and egg yolks to the sugar mixture and whisk to combine thoroughly.
Add the Meyer lemon juice and whisk to combine.
Pour the mixture into a medium sauce pan, and place over a medium low heat. Add the butter. Stir continuously to keep the mixture moving so your eggs don't scramble.
Cook the curd until thick and just beginning to bubble, or until an instant read thermometer reaches 170F. The curd will thicken more in the refrigerator.
Strain the curd into a clean shallow bowl, and let it sit until it reaches room temperature.
Pour the curd into your cooled, fully baked tart shell. Use a spatula to spread the curd evenly in the tart shell. Place in the refrigerator to set up the filling, about 4 hours.