In a medium-sized Pyrex or other ovenproof bowl, combine 3 oz. butter, 1 T. vegetable oil, 3 T. water, 1 T. sugar, and a pinch of salt.
Place in an oven at 400 degrees for 15 minutes, until the butter is bubbling.
Remove from the oven and add 1 C. all-purpose flour. Stir quickly to combine until a ball of dough forms. Transfer the dough to a 9″ tart pan or pie pan. Spread a bit with a spatula and then allow it to cool.
Once the dough is cool, press it into the pan evenly with your fingers. Prick it all over with a fork, then bake in the oven for 15 minutes.
While the shell is baking, make the filling. Combine 1/4 C. Mascarpone and1/4 C. sugar in a mixing bowl. Beat by hand or in an electric mixer until the combination is light and fluffy. Add 1 3/4 C. ricotta cheese, 1 egg plus 1 egg white, 1 t. honey, and a pinch of salt. Mix to combine.
Pour the filling into the tart shell — it’s okay if it’s still hot. Bake 20-30 minutes, until the filling is just set in the center.
Just before serving, top the tart with fresh ripe fruit.