Ricotta and Lemon Pastry Tart

In a large bowl, mix together the flour, sugar, vanilla extract and salt. Add the butter and egg yolk, and work the dough together by hand. Gradually add the Limoncello, 1 ounce at a time, working Limoncello into the dough. Continue adding the Limoncello until you get to the point where you can shape the dough into a ball. 2. Transfer the dough to a lightly floured work surface, and roll out the pastry until it is slightly larger than your tart pan (use a 9 or 10-inch pan). Gently ease the pastry into the tart pan, pressing the dough up the sides of the pan. Trim any excess dough and prick the bottom with a fork. Refrigerate to chill for at least 30 minutes. 3. Preheat oven to 350°F. 4. Zest two lemons and set the zest aside. Extract the juice from one of the zested lemons and set the juice aside. 5. In a glass bowl, cream together the 2 eggs, 3/4 cup sugar and cornstarch. Fold in the Ricotta cheese, and mix well. Add the lemon zest and juice; mix to incorporate. Pour the filling into the chilled pastry shell. Bake for 45 minutes, or until done. Remove from oven and allow to cool. 6. Thinly slice the remaining two lemons, and cut the slices into quarters. Mix the remaining 1/2 cup sugar with 10 tablespoons of water. Pour into a skillet and bring to a boil. Add the lemon slices; lower the heat to a simmer and simmer the lemon slice for 5 to 6 minutes. Remove from heat and cool. 7. Place the sugared lemon slices on the tart before serving. Dust with confectioners' sugar. Serve.