Juana Molina has built up a global cult following as one of the most experimental musicians in Argentina, an exponent of folktronica who mixed acoustic styles and electronics. With her new album, Wed 21, she has added electric guitar, bass and drums to the mix, but it's still a solo work – she performed, recorded and produced it herself, crafting each song by adding layer upon layer of sound.

Both of the one-time queen of Latin chill's UK concerts this week are in churches. Yet when, an hour into the set, she first addressed her audience, it was to announce "heavy metal is not my kind of music, but it would be great to be in a heavy-metal band". She then broke into a burst of frantic guitar work.

Those expecting the quirky charm she showed when she first played here nine years ago might have been startled. Flanked by a second guitarist and a drummer, she began in attacking form, with songs built around simple, gutsy guitar riffs that were sampled and repeated, as extra layers of guitar, keyboards, electronic effects or vocals were added in. At first the results sounded impressive but conventional – it was like listening to a guitar band with a good line in riffs and sound loops.

But then she began to show the subtlety and invention of the new album, adding exhilarating layers of vocal effects, from the breathy to the passionate, in increasingly complex constructions that were always strong on melody and rhythm. The presentation was deadpan, but there was one joke (in English), before she ended with a solo encore that began as an acoustic number and ended with a wash of effects. She is still a true original.

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