The problem can be fixed with this redefinition of \step
\documentclass{article}
\usepackage{xcookybooky}
\renewcommand{\step}
{%
\stepcounter{step}%
\lettrine
[%
lines=2,
lhang=0, % space into margin, value between 0 and 1
loversize=0.15, % enlarges the height of the capital
slope=0em,
findent=1em, % gap between capital and intended text
nindent=0em % shifts all intended lines, begining with the second line
]{\thestep}{}%
}
\begin{document}
\begin{recipe}{Back}
\preparation{%
\step test
}
\end{recipe}
\end{document}
This problem was fixed in the github version of the xcookybooky
package available from https://github.com/SvenHarder/xcookybooky