Make a four-fold puff pastry from the butter and flour (or use good quality shop-bought puff pastry), and roll out to the thickness of a knife-back.
Line small, buttered tartlet or muffin molds with it, and blind-bake (with a weight) in a preheated oven at 200°C for 15-18 minutes, until golden and crisp.
For the filling, make a light roux from the butter, add the finely chopped mushrooms, onion and parsley, and braise for a few minutes.
Add the broth and the cream, season with salt and pepper, and cook down for 4-5 minutes until thick.
Stir in the cubed roasted veal, and warm through.
Right before serving, fill the baked pastry shells with the hot filling, and serve immediately, warm.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.