Described are a cocktail preparation system, a liquid measuring and mixing device, and a method of measuring and mixing liquids. A liquid measuring and mixing device involves a measuring cup comprising a circular cross-section and one or more protruding cavities thereof joined by a plurality of support members spanning a length of the circular cross-section, the one or more protruding cavities being of calculated volumes for the purpose of accurately measuring volumes of liquid. A cocktail preparation system includes the measuring cup as described in addition to a mixing cup within which the measuring cup fits to form a sealed cocktail shaker for the purpose of mixing of the measured volumes of liquid. A method of measuring and mixing liquids involves accurately measuring two or more volumes of liquid in the measuring cup, placing the measuring cup within the mixing cup, and subsequently shaking the combination to create a cocktail.