Make crust: Pulse together flour, cornmeal, sugar, and salt in a food processor. Add butter and rosemary and pulse until mixture resembles coarse meal with some small (roughly pea-size) butter lumps. Drizzle evenly with 4 tablespoons ice water and pulse until just incorporated.
Gently squeeze a small handful: If it doesn't hold together, add more water, 1/2 tablespoon at a time, pulsing after each addition and continuing to test.
Press dough evenly onto bottom and up sides of tart pan with floured fingers. Smooth dough with a small offset metal spatula or back of a spoon (floured if necessary), then roll a rolling pin over top of pan to trim dough flush with rim. Chill crust until firm, about 30 minutes.
Preheat oven to 400°F.
Bake crust in middle of oven until center and edges are golden, 25 to 30 minutes (don't worry if bottom of crust cracks), then cool in pan on a rack.
Prepare filling and assemble tart: Whisk together sour cream, mascarpone, sugar, zest, and salt in a bowl.
Heat jelly and honey in a small saucepan over moderately low heat, whisking, until jelly is melted, about 4 minutes, then cool glaze slightly.
Remove side of tart pan and spread mascarpone cream in shell. Cut figs lengthwise into 1/4-inch-thick slices and arrange decoratively over cream. Brush figs with honey glaze.
· Crust can be made 1 day ahead and kept, covered, at room temperature. · Mascarpone mixture can be made 1 day ahead and chilled, covered. · Tart can be assembled 1 hour ahead and kept, loosely covered, at room temperature.