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 NiCl[subscript 2], 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.