You can simply use XmlSlurper class that is very similar to JsonSlurper. Assuming this is your's XML, you can do something like this:
def xml = '''<?xml version="1.0" encoding="UTF-8"?>
<breakfast_menu>
<food>
<name>Belgian Waffles</name>
<price>$5.95</price>
<description>Two of our famous Belgian Waffles with plenty of real maple syrup</description>
<calories>650</calories>
</food>
<food>
<name>Strawberry Belgian Waffles</name>
<price>$7.95</price>
<description>Light Belgian waffles covered with strawberries and whipped cream</description>
<calories>900</calories>
</food>
</breakfast_menu>
'''
def root = new XmlSlurper().parseText(xml)
assert root.food[0].name.text() == 'Belgian Waffles'
Keep in mind that new XmlSlurper().parseText(xml) returns a node that refers to the first (root) XML node element. Then you can do almost the same manipulations that are available for JsonSlureper class.