1) To make the crust: Whisk together the flour, sugar, and salt. Mix in the butter until evenly crumbly.
2) Add the egg yolk, mixing till the mixture holds together when squeezed.
3) Press the dough into a 9" tart pan, pushing firmly up the sides. Prick the crust all over with a fork. Chill in the freezer, uncovered, for 15 minutes or so, while you preheat the oven to 375°F.
4) Bake the tart crust for 15 to 20 minutes, until lightly browned around the edges. Remove from the oven.
5) To make the filling: Mix the softened cream cheese with the sugar until well blended, making sure to scrape the sides and bottom of the bowl.
6) Mix in the eggs one at time, then the cream, Fiori, and zest.
7) Pour the filling into the baked crust. Reduce the oven heat to 350°F. Bake for 20 to 25 minutes, till the tart is nearly set; a small spot in the middle will remain soft-looking.
8) Remove from the oven, and cool at room temperature for 1 hour; then refrigerate till ready to serve.
9) Just before serving, top as desired with fresh fruit, and brush with apricot jam that's been thinned with water, heated gently, and strained to remove the solids.
Yield: one 9" tart, 6 to 8 servings.