Two semi-final heats were held in front of a captivated crowd at Griffith Central, with local high school student Nathan Wells continuing his phenomenal rise to progress through to this week's decider, along with local accountant Amanda McLeod and former WIN sportscaster Luke Testoni.

Each contestant was given a basket of goods and could choose one additional ingredient to complement each course.

They then had 90 minutes to whip up a main and a dessert and the result, according to Masterchef judge and Griffith Central manager Cheryl Wood, was "simply spectacular".

"In the women's heat, they all produced something special and we really struggled to separate the dishes," Mrs Wood said.

"But Amanda's dish did have the X-factor, in particular her dessert - an orange marmalade pudding - which scored full points across the board."

Mrs Wood said Ms McLeod, who cooked a chicken dish for her main, had produced "amazing" dessert dishes all the way through the competition.

She defeated Marguerite Sergi and Vicki Wade to qualify for the grand final.

In the men's afternoon heat, schoolboy Nathan Wells showed talent is as important in the kitchen as experience, whipping up a crumbed chicken breast stuffed with Philadelphia cheese and veggies and a cheesecake with toffee shards.

Nathan's attention to detail won the judges over, with his squash being parboiled and then finished off with stuffed capsicum.

He won the heat to earn a spot in the final, defeating local accountant Ken Cheers and Luke Testoni, who earned a wild-card entry into the decider.

The grand final challenge remains top secret and will be revealed just before this weekend's cook-off at 10.30am at Griffith Central.