How to Make It
In a medium saucepan, bring the fish stock to a boil over moderately high heat. Remove from the heat and stir in the saffron. Cover and set aside for 10 minutes.
Melt 1 stick of the butter in another medium saucepan. Add the flour and whisk over moderately high heat until smooth and bubbling, about 3 minutes. Add the fish stock and boil, whisking often, until thickened, 3 to 5 minutes. Stir in the cream, season with salt and pepper and remove from the heat.
Preheat the oven to 400°. Arrange the pastry shells on 2 baking sheets and brush the tops with the beaten egg. Bake for about 25 minutes, or until golden brown and cooked through. Scoop out and discard the doughy center from the shells. Turn the oven off and keep the shells warm inside.
In a large skillet, melt the remaining stick of butter. Add the garlic and minced dill and cook over moderately high heat, stirring often, until fragrant, about 2 minutes. Add the wine and boil for 6 minutes; discard the garlic. Add the shrimp and cook, turning often, until pink and firm, about 5 minutes.
Rewarm the cream sauce over low heat. Divide the shrimp among the pastry shells and spoon the sauce on top. Garnish with the dill sprigs and serve.