Abstract: Substantially uniform distribution of a particulate composition such as a seasoning or spice, on both the top and bottom surfaces of baked good or snack pieces is achieved by applying the composition as a curtain or sheet from within a housing as the substrate pieces are transported and tumbled by counterrotating brushes. The curtain or sheet extends in the direction of the longitudinal axis of the longitudinal cavity through which the substrate pieces are transported. The apparatus includes a housing having a raised portion for enclosing and permitting the curtain or sheet to disperse in a direction transverse to the longitudinal axis of the housing cavity as the composition descends towards the baked good or snack pieces. A lowered portion, downstream of the raised portion of the housing prevents escape of airborne particulate composition to the atmosphere through the baked good or snack piece outlet.