Remove the dried beef from the package and rinse under cold water. Pat dry with paper towels and chop into 1/2-inch pieces.
In a large skillet over medium heat, melt the butter.
Sprinkle the flour over the melted butter and whisk for 1 minute to cook out the raw flour taste.
Gradually whisk in the milk, a little at a time, ensuring no lumps form.
Continue to cook, stirring frequently, until the sauce thickens and reaches a simmer.
Stir in the chopped beef and black pepper (and nutmeg if using). Reduce heat to low and simmer for 2–3 minutes.
While the beef simmers, toast your bread slices until golden brown and butter them lightly.
Spoon the warm beef and gravy generously over the toast.
Garnish with fresh parsley and extra black pepper if desired. Serve immediately.