\documentclass{article}
\usepackage{german}
\newcounter{num}
\newenvironment{varlist}[2]
   {\begin{list}{\textrm{#1 #2{num}:}}{\usecounter{num}%
       \setlength{\labelsep}{5mm}
       \settowidth{\leftmargin}{\textrm{#1 #2{num}:}}
       \addtolength{\leftmargin}{1cm}}}
   {\end{list}}
\begin{document}
\noindent Vorangehender "au"serer Text
\begin{varlist}{Muster}{\Alph}
   \item ohne Wert
   \item mit beigef"ugtem Gutschein
\end{varlist}
\end{document}
 
