Add single unicode character (euro symbol) to font under Xe(La)TeX

Question

Maybe this has already been asked, but I could not find an answer.

I just switched to XeTeX because I need to use a .ttf font in my project. Everything works fine except that the euro (€) symbol is missing from the font. How can I tell XeTeX to use a different font only for that character?

Someone pointed to ucharclasses but I couldn't understand how to set it up to do what I need (besides, I am not sure it is what I am looking for, as it deals with blocks of text, not single characters)

Here is my current setup:

\usepackage[math-style=ISO, bold-style=ISO]{unicode-math}
\setmainfont{Simoncini Garamond}
\setsansfont{TeX Gyre Heros}
\setmathfont{Garamond-Math.otf}[StylisticSet={7,9}]

Answer 1

The simplest solution is to find a font that has a good € glyph, say “Best Font”.

Now add

\usepackage{newunicodechar}

to your list of packages and, after your font settings, the magic formula

\newfontfamily{\eurofont}{Best Font}[Scale=MatchUppercase]

\newunicodechar{€}{{\eurofont €}}

Typing € in the document will do. You might want to use an indirection:

\newfontfamily{\eurofont}{Best Font}[Scale=MatchUppercase]

\DeclareRobustCommand{\EUR}{{\eurofont €}}
\newunicodechar{€}{\EUR}

so as to be able also to type \EUR for the glyph.