Prepare No-Fail Tart Crust as directed, except at the end of Step 3 sprinkle dough with 2 Tbsp. chopped thyme leaves; press into crust.
Increase oven temperature to 450 degrees F. In a shallow baking pan toss carrots with olive oil and salt. Roast 15 minutes or until crisp-tender and caramelized, stirring once. Remove from oven; set aside. Stir mascarpone to soften; spread over crust. Top with roasted carrots. Bake 5 minutes or until heated through. Cool slightly. Sprinkle with thyme leaves; drizzle with honey.
No-Fail Tart Crust
Preheat oven to 450 degrees F. (For nonstick pans preheat oven according to instructions on package.) In a food processor pulse flour, butter, and salt 10 to 20 seconds or until mixture looks like fine crumbs. Do not overprocess.
In a small bowl whisk together yolks and the water. With processor running, add yolk mixture. Stop as soon as dough just starts to come together, about 5 seconds.
Crumble to distribute evenly in an 118-inch rectangular tart pan or 11-inch round pan with removable bottom; press into pan. (Or gather dough into a ball; flatten. Roll out dough between two pieces of parchment paper into a 129-inch rectangle. Transfer dough to pan. Press into corners; trim excess.)
Using a fork, prick dough all over. Line pastry with a double thickness of foil. Bake 12 minutes. Reduce temperature to 350 degrees F. Remove foil. Bake 8 minutes more or until pastry is golden. Let cool completely. Use baked crust to prepare seasonal tarts.