Direction

1. Preheat oven to 325°F. Crush saffron threads between fingers, and place in a small bowl. Stir in wine; set aside.
2. Melt 4 tablespoons butter in a Dutch oven over medium. Add onions and 1/2 teaspoon salt. Cover and cook, stirring often, until onions are very tender but not browned, about 20 minutes. Add rice and saffron mixture; cook, stirring constantly, until wine is absorbed, about 1 minute. Add clam juice; cook, stirring constantly, until liquid is mostly absorbed, about 4 minutes. Remove from heat, and cover Dutch oven tightly with aluminum foil.
3. Transfer Dutch oven to preheated oven, and bake until rice is tender and liquid is absorbed, about 15 minutes. Uncover Dutch oven; stir in shrimp and 1 teaspoon salt. Cover and let stand at room temperature until shrimp are partially cooked, about 10 minutes. Meanwhile, microwave remaining 1 tablespoon butter in a small microwavable bowl until melted, about 20 seconds. Stir in panko, 2 tablespoons Parmesan, and a pinch of salt; set aside.
4. Increase oven temperature to 425°F. Drain artichokes, reserving 1/4 cup marinating liquid; discard remaining marinating liquid. Uncover Dutch oven, and stir in artichokes, reserved 1/4 cup marinating liquid, crème fraîche, tarragon (if using), remaining 3/4 cup Parmesan, and remaining 3/4 teaspoon salt. Divide mixture evenly among 4 (16-ounce) ramekins, and sprinkle evenly with panko mixture. Place ramekins on a baking sheet.
5. Bake gratins at 425°F until tops are golden brown, about 15 minutes. Let stand 10 minutes before serving. Garnish with microgreens, if desired.