Abstract: An improved food preparation device for tenderizing and injecting marinade into a food product is contemplated. In one aspect, the device includes one or more needles having features for improved marinade dispersion. In another aspect, the device may include an adjustable guard configured to cause marinade to be injected when a bottom surface of the adjustable guard impacts a food surface. The amount of marinade injected is related to the distance the adjustable guard or plunger travels thereby providing even marinade distribution through the food being prepared. The configuration also provides a variable marinade flow rate related to a force applied to the device or the speed at which the device is operated. The adjustable guard may be vertically adjustable relative to an outlet end of the needles to allow the depth of penetration of the needles to be precisely controlled prior to initiation of marinade injection.