1. In a large, enameled cast-iron casserole, melt the butter in the oil. Add half the veal, season with salt and pepper and cook over moderately high heat, turning, until browned on all sides; transfer to a plate. Repeat with the remaining meat.
2. Add the shallots and prosciutto to the casserole and cook over moderate heat, stirring, until the shallots are softened, about 3 minutes. Add the wine and cook over high heat until reduced by half, about 4 minutes. Return the veal and any accumulated juices to the casserole. Add the stock, carrots and thyme. Bring to a boil, then simmer over low heat until the veal is very tender, about 1 1/2 hours.
3. Cook the asparagus in a saucepan of boiling salted water until tender, about 8 minutes. Drain; cut into 2-inch lengths.
4. Add the heavy cream to the casserole and simmer until slightly reduced and flavorful, about 5 minutes. Season with salt and pepper. Add the asparagus pieces, simmer 1 minute longer and serve.
Make Ahead: The stew can be prepared through Step 2 and refrigerated for up to 2 days. Reheat gently before continuing with the recipe.
Serve With: Mashed potatoes, buttered noodles or steamed rice.