Star, still in the hunt for the Lothian East league title, claimed their first silverware of the season in convincing fashion as they swept aside their Wardie-based opponents.
It was ideal preparation for their head-to-head with Chirnside, who will provide a stern test of this Star side's credentials at Innerleithen.
A crowd of around 150 at Saughton Enclosure saw man of the match Ian McManus plunder a goal in each half to consign Broughton to their first defeat in 14 games.
The roving midfielder, a former star of Easthouses in the East of Scotland League, lit up the game with his mazy runs and keen eye for goal, and proved the match winner with a performance that would have eased his personal pain of missing out on the Scotland Amateur team, trials for which he attended the previous week.
The first of his brace of strikes arrived after 12 minutes. Broughton defender Mark Kennedy had done well to snuff out the threat of one 'Nitten' attacker but turned into trouble on the edge of the area, losing possession to McManus, who dragged the ball towards goal and slotted past Aaron Griffiths.
A flowing Star move on 20 minutes was, aesthetically-speaking, deserving of a second goal. John McManus drove up the right flank before dinking the ball inside for namesake Ian, whose quick thinking and fleet-footedness played John Jenkin through on goal. Griffiths, however, was alert and managed to race off his line to smother the ball before Jenkin could shoot.
Broughton had plenty chances to equalise, with Alan Morrison and Kennedy striking long-range efforts that narrowly cleared the goal frame, and Gary Low seeing his 15-yard effort brilliantly held by the standout 44-year-old Star goalkeeper, Steven Hay.
A slip by 'Nitten' defender Paul Smith allowed John Kane to collect possession just ten yards from goal, but Steven Dorans timed a crucial intervention to perfection and slid the ball clear.
Broughton's profligacy was punished early in the second half as their defenders could only partially clear their lines from a John McManus cross, Ian McManus coolly netting his second of the game by firing past Griffiths. Star goalie Hay denied Brian Thompson and Alan McCrindle with two top-drawer saves midway through the second period, but the final chance of the game fell to Newtongrange.
After conjuring a neat set piece, Jenkin playing a short free kick to Ian McManus, who then completed the triangle by knocking the ball into the box for namesake John, the 'Nitten' No.10 saw his shot fly narrowly wide.
Alan Scotland, the Newtongrange secretary, felt his side, led by manager Paul Neilson, was destined for victory from the start. "It's the icing on the cake for us. We're in the South of Scotland Cup final and still in the hunt for the league.
"We had that hunger, and as soon as we went onto the park I knew we were going to win. Broughton played well, though, and I thought it was a good game to watch."
Meanwhile, Broughton boss Ally Handyside had done his homework on Newtongrange but was still powerless to prevent defeat. "I went to see Newtongrange twice. They are a decent side, very competitive.
We were lacking all over the pitch. It was one of these games where the boys didn't turn up. We've been scoring goals for fun this year."
Newtongrange Star 'A': Steven Hay, Paul Smith, Steven Dorans, Ian McManus, Michael Thomson, William Mason, James McDougall, John Jenkin, Steven Nethery, John McManus, Gary Irvine, Sean Bingham, Kevin Smith, Scott Beattie, Alan McGowan, William Sives.
Broughton: Aaron Griffiths, Alan McCrindle, Darren Hope, Mark Kennedy, Ryan Rodgers, Chris Malone, Terry Lind, Alan Morrison, John Kane, Brian Thompson, Gary Low, Steven Smith, Jeff Lind, Alan Anderson, Euan Bell, Leon Grieve.