Arrange a rack at a center position and preheat the oven to 375 F. Have ready a 9-inch tart pan with a removable bottom.

For the crust: Place the flour, cream cheese, butter, salt, and cayenne in a food processor; pulse until the mixture resembles coarse meal. Remove and knead the mixture into a smooth mass and then press it with your fingers in an even layer into the bottom (not up the sides) of the tart pan. Smooth the dough with the back of a spoon. Freeze the tart shell for 15 minutes to firm, and then bake the crust until golden brown, 30 minutes. Remove the tart shell from the oven and cool for about 5 minutes but retain oven temperature.

For the topping: Sprinkle the cheese evenly over the crust. Arrange the tomatoes in a circular pattern and in a single layer over the cheese, cut-sides up. You may not need to use all of the tomatoes. Whisk together the olive oil and vinegar and drizzle over the tomatoes, and then sprinkle with salt. Place the tart on a baking sheet to catch any drippings and return to the oven and bake until the cheese has melted and the tomatoes are hot, 10 to 12 minutes.

Cool the tart for 5 to 10 minutes and then remove the sides of the tart pan. (The tart can be made 3 hours ahead. Leave the tart cool at room temperature and reheat in a preheated 350 F oven until warmed through, 8 to 10 minutes.)

Mix together the parsley and green onions, and sprinkle over the tart. Cut the tart into 6 wedges and serve.

Note: Small grape tomatoes, which have a sweet flavor, work better than larger cherry tomatoes in this recipe and can be used year-round. However, in the summer, feel free to try the tart with one of your favorite varieties. Sweet ones that are on the small side work best.