Full text catalog does not allow me to hit on singular forms
You could use either CONTAINS with FORMSOF(INFLECTIONAL, smörgås) or FREETEXT

CONTAINS:

SELECT pc.SearchData from PageContent pc
WHERE CONTAINS(pc.SearchData, 'FORMSOF(INFLECTIONAL, smörgås)', LANGUAGE 'Swedish')


FREETEXT (includes INFLECTIONAL and some other stuff automatically):

SELECT pc.SearchData from PageContent pc
WHERE FREETEXT(pc.SearchData, 'smörgås', LANGUAGE 'Swedish')