We present an experiment designed to hone the decision-making skills of (undergraduate) chemistry students by using aqueous crossed aldol reactions. Here, we present two simple crossed aldol reactions based on inexpensive and readily available materials: The condensation of vanillin and cinnamaldehyde with acetone. The procedure uses the variation of reaction conditions (including the use of inexpensive chlorides, namely LiCl or NiCl2, as catalysts and variation between different mild reaction temperatures), as well as different simple preparative and analytical techniques such as filtration, recrystallization, melting point measurements, thin-layer chromatography and IR spectroscopy aiming for the students to find the optimal reaction conditions, thus honing their decision-making and time management skills. Furthermore, those experiments are designed for a laboratory session of 3 to 4 h.