Melt the butter in a small pot and, once melted, slowly add the flour, mixing with a whisk to obtain a well-mixed roux. Add the hot milk and dilute the mixture, mixing well with the whisk. Continue mixing, cooking on a low heat, until the mixture thickens.
Remove the small pot from the heat and mix the Granello (grain) slowly, a little at a time.
Mix thoroughly: the cream must be solid enough so that, if lifted with a spoon, it stays on the surface for a while before falling off.
Serve the cream to taste.