Creating their own menus, the three semi-finalists had to put it all on the line to serve up their best to a room full of diners and the three judges and prove they deserve a spot in Sunday's grand finale.
From the get-go, Declan wasn't going to make it easy on himself and had designed his menu to really push himself and impress the judges.
"I thought, semi-finals... I'm going to go hard or I'm going home. And I ended up doing both," he told 10 Play with a laugh. "I went hard and I obviously went home. I wasn't going to do a simplified version.
"When we were at Top 10 and I made that apple crumble... don't get me wrong, it was delicious, but as the judges said it wasn't Top 10 worthy," he continued. "It was a moment for me where I pivoted and I was like, alright, you're here on MasterChef... here I am in the semi-finals, I really wanted to bring my A-game."
Knowing he was going to be up against the clock, Declan wanted to serve three elevated dishes to "blow the judges out of the park and be restaurant-worthy".
Serving up three courses of Scampi toast, a Blue-Eye Trevalla with Green Curry and finishing it out with his take on a Paris Brest, Declan was clearly under the pump.
"Being able to curate my own personal menu for dishes that I'm obsessed with, I think it was so special to be able to share that, not just with the judges but the other diners who were going to be joining us that evening," he said, adding, "I was definitely very ambitious in my menu planning."
With just four hours on the clock, Declan said it wasn't until his last dessert left the pass that he actually looked up and was able to see diners enjoying his food.
"I couldn't believe that I had done an entree, main and dessert for all these people, and I managed to get all the dishes out," he said. "There were a couple of speed bumps along the way, but I think I said to myself that was just crazy.
"I've done a few crazy things in my life like walking Kokoda and having a cage fight... that's got to be up there with one of the craziest things I've ever done," he laughed.
But during the challenge, even Declan admitted to himself that he may have bitten off more than he could chew -- or choux -- the reality set in that the timing may not have worked in practice even if it did on paper.
With the heartbreaking news that he wouldn't be going onto the grand finale, Declan still said he was thrilled with what he was able to achieve in the competition.
"I think it's a bit cliché but I definitely didn't see myself getting this far... it's quite amazing watching myself evolve and seeing how I did really push myself in that high-intensity, high-pressure situation," he added.
Declan said he's always loved being creative in the kitchen, "I was a bit of a chubby kid growing up so I always used to love licking the back of the spoon when mum was making the cakes and sweets," he added.
That curiosity around food turned into a love of restaurants as he got older, where he'd then try to recreate dishes he loved at home.
"Before I was in a relationship I was happy to go and solo dine at a restaurant and really explore the menu and what they had to offer," he said. "I've always been a huge foodie."
Coming into the competition as "the fish guy", Declan soon became the everything guy, finessing his skills across the board, tackling intricate dessert pressure tests and flavours from across the world.
"I came in with the mentality that I wasn't not going to give anything a go. Being on MasterChef, you can't refine your cooking to one cuisine or one certain thing," he told 10 Play.
"I was always willing to explore the different methods of cooking and techniques and just really immerse myself in the whole experience. I left everything behind to be a part of the competition so I wasn't going to go down easy and I think that mentality of giving everything a go really shone through."
Something else that really shone through was Declan's huge heart and, on multiple occasions, his willingness to help the other chefs even when his own place in the competition was at risk.
"Yeah I think I had to remind myself that sometimes it is a competition," he said, laughing. "But I think that just shows the kind of person I am. If someone is ever in need or struggling, I’ll always put my hand out to help them and it was really lovely, I’ve received so many humbling messages, especially about helping Theo the other day... [I'm] just here to help people and I definitely forgot that $250,000 was at stake."
Fresh out of the MasterChef kitchen, Declan has his foot in the door of the culinary world and he's ready to throw himself into it fully.
"There are definitely some things in the pipeline," he teased, "I can see myself catching up with some of the contestants I really bonded with, doing a bit of a catch-and-cook cooking show, networking with other people in the industry and just trying to figure out where I would be best be suited.
"The world is my oyster and I'm not going to turn down any opportunities that come my way."
Don't miss the MasterChef Grand Finale Sunday, July 16 at 7.30 on 10 and 10 Play