This time Spike isn't adding anything to his blood. Just heating it up to a temperature as close to 'human' as he can get it. Not that he can't have it cold, but he prefers it hot. It's also just about done, so he kills the heat and brings the pan over for Maurice to see.

Nothing but blood by the look and smell.

Enough for the other vampire to verify it, before Spike is carefully pouring it in the mug. The pan goes in the sink with water running for a quick rinse while he grabs his mug. Bringing it up for a drink, and his face changes in that strange naturally-unnatural way. Clearly the elder vampire is pleased, and in a decent mood. Comfortable with his game-face, as it's just himself and Maurice. Usually Spike wore his human-face to make others comfortable.