Notice how I've not called this a hack for making homemade prosecco ... I couldn't taste the difference when I used regular white wine in my InFizz Fusion, I don't want to start my 2025 with ...

you can double or quadruple the wine and sugar quantities but leave the rest the same. Making mulled wine in the slow-cooker is completely hands off, but do give it a couple of hours to heat up.