The Englishman produced a decisive late surge to overturn a 5-4 deficit, reeling off four consecutive legs to seal the £35,000 top prize. Aspinall averaged 100.35 and struck seven 180s in a composed closing display, ending the contest with a 128 checkout.
The win marks his fourth European Tour success and draws him level with Phil Taylor for career titles in the series.
Aspinall's route to the title included a series of strong performances across finals day. He recovered from 2-0 down to defeat Germany's Martin Schindler 6-2 in the third round, winning six straight legs. That was followed by a 6-4 quarter-final victory over Andrew Gilding.
His most emphatic display came in the semi-finals, where he averaged 106.40 in a 7-2 win against Kevin Doets, ending a run of six consecutive defeats against the Dutch player.
In the final, Aspinall took early control, opening up a 4-1 lead with the help of an 11-dart leg and a 108 checkout. However, Noppert responded with four successive legs to move ahead at 5-4, capitalising on a brief dip in Aspinall’s doubling.
The turnaround proved short-lived as Aspinall regained control with legs of 13, 12 and 15 darts before sealing victory.
"I am absolutely buzzing," Aspinall told the PDC. "I have had a lot of knockbacks this year. I have been trying to keep myself motivated and sometimes it is hard, but nights like tonight are why we play this game.
"I did an interview on Saturday, saying I was trying to find that love for the game again, but Munich gave me the love for darts again."
Noppert, appearing in his fourth European Tour final, delivered a consistent run to reach the showpiece. The Dutchman defeated Karel Sedlacek, Jonny Clayton and Krzysztof Ratajski on finals day, conceding just five legs across those three matches.
"I am really happy to be in the final again," Noppert said. "I did not show up in the final, and Nathan was the deserved winner.
"Of course, I wanted to lift the title. There is another level I can go to, and I am pushing myself hard every time."
Elsewhere, Ratajski impressed in reaching the semi-finals, averaging close to 99 across victories over Ryan Searle and Ross Smith, before defeating Michael Smith 6-2 in the quarter-finals.
Doets reached his first European Tour semi-final, producing a standout performance in a deciding-leg win over Dirk van Duijvenbode, where he averaged 107.7 and hit ten 180s. He also survived three match darts in his quarter-final win against Niels Zonneveld.
Zonneveld's run to the last eight included a 103 average in his victory over Josh Rock, while Clayton recorded a 104.78 average in his win against Kim Huybrechts during the third round.
The PDC ProTour season continues with Players Championship events in Wigan on April 13th, before the European Tour resumes in Sindelfingen from April 17th.