I myself prefer to use em dashes in this case, but spaced en dashes are an accepted alternative: The Chicago Manual of Style §6.89 “En dash as em dash” > In c

I myself prefer to use em dashes in this case, but spaced en dashes are an accepted alternative: The Chicago Manual of Style §6.89 “En dash as em dash” > In contemporary British usage, an en dash (with space before and after) is usually preferred to the em dash as punctuation in running text – like this – a practice that is followed by some non-British publications as well. See also 6.91. The Elements of Typographic Style §5.2.1 “Use spaced en dashes…” > Use spaced en dashes – rather than close-set em dashes or spaced hyphens – to set off phrases. > […] > In typescript, a double hyphen (--) is often used for a long dash. Double hyphens in a typeset document are a sure sign that the type was set by a typist, not a typographer. A typographer will use an em dash, three-quarter em, or en dash, depending on context or personal style. The em dash is the nineteenth-century standard, still prescribed in many editorial style books, but the em dash is too long for use with the best text faces. Like the oversized space between sentences, it belongs to the padded and corseted aesthetic of Victorian typography. Used as a phrase marker – thus – the en dash is set with a normal word space either side.