%TODO: last line is not great
\begin{tabular}{@{}>{\bfseries} p{0.15\textwidth}rlrl@{}}
\toprule
      & \multicolumn{2}{c}{\thead{Flat breads}} & \multicolumn{2}{c}{\thead{Pancakes}} \\ \midrule
Flour             & 100g   &           & 100g   &           \\ 
Water             & 100g   & (100\%)   & 300g   & (300\%)   \\ 
Sourdough starter & 5--20g & (5--20\%) & 5--20g & (5--20\%) \\ 
Salt              & 2g     & (2\%)     & 2g     & (2\%)     \\ 
Bake when?        & \multicolumn{2}{c}{Dough increased by 50\% in size.}
                  & \multicolumn{2}{c}{Bubbles visible on surface.}\\
\bottomrule
\end{tabular}