In a bowl, mix together butter, sugar, salt, and lemon zest.
Work in flour until combined, then add the egg yolk and mix until a dough forms.
Wrap dough tightly in cling film and refrigerate for 1 hour.
Remove dough from fridge and bring to room temperature, 10-15 minutes.
Roll into a circle and place in a 10” tart shell, forming the dough to the bottom and sides. Cut excess and chill in fridge for 30 minutes.
Preheat oven to 350°F. Remove tart from fridge and place directly in oven for 30 minutes until golden.
In another bowl, mix together ricotta, egg, sea salt, lemon juice, and Parmesan. Transfer to tart shell and place back in oven to cook for 5-10 minutes.
While tart is cooking, halve cherry tomatoes and mix with olive oil, sea salt, and chopped fresh basil.
Remove tart from oven and let cool for 10-15 minutes. Remove from tart tin and transfer to a plate.
Top tart with tomato mixture and sprinkle on more fresh basil.