Laura May-Walkley put the champions ahead after 18 minutes with a low drive into the net, but Cascade levelled in 42nd minute when Abbie Davies finished off a quick break away.
However, Ferry were back in front in first half stoppage time as Lucy Powell struck a superb free-kick past Bethan Connolly and Walkley scored her second of the game early in the second half to give her side a cushion.
The Reds lifted the Genero Adran South trophy after the game and they will now have their eyes set on promotion to the Genero Adran Premier.
Jade Crofts stole the show at Parc Ynysderw as her hat-trick steered Cwmbran Celtic to an entertaining 3-2 win over Pontardawe Town, which extended their unbeaten league run to six matches.
Crofts scored twice in the first half and things looked to be going smoothly for Celtic, but quickfire goals midway through the second half from Catryn Cook and Sara Llewelyn suddenly drew Ponty level.
However, the hosts simply couldn’t deal with Crofts’ quality in attack as the forward completed her hat-trick in the 79th minute for her 15th goal in her last ten matches in all competitions.
Millie Pearce’s late strike earned Caldicot Town just a second win of the season as they defeated Llanelli Town 1-0 at Jubilee Way.
The decisive moment came in the 87th minute as Pearce took aim from 30 yards out and sent a fantastic effort beyond Jo-Anna Nowak-Allum, condemning the Reds to a fifth successive league defeat.
Genero Adran South results
Briton Ferry Llansawel 3-1 Cascade
Caldicot Town 1-0 Llanelli Town
Pontardawe Town 2-3 Cwmbran Celtic
