Actually, a half & half - BUT maybe that is regional to where there are large Irish populations.
In Chicago, in at least any bar worth a salt, a Black & Tan is Guinness & Bass (an English beer), whereas a half & half is Guinness & Harp.
Both Guinness & Harp are Irish beers and because the Royal Irish Constabulary Reserve Force was nicknamed the Black & Tans & were sent to Ireland in the 1920s to suppress the Irish, the Irish never refer to any beer combination as a Black & Tan.
If only they had a much lighter caramel colored bowl with the Harp logo on it, combined with that Guinness lid with kind of a foam "fade" on the top.
Black and tan
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