O’Sullivan won the Award, which also includes a prize of £200,000, after impressing in MSV Formula 2, BBM Ginetta LMP3 and Garage 59 Aston Martin GT3 machinery last year.
He completed a day of testing at the Silverstone Grand Prix circuit in one of Aston Martin’s AMR21 cars on Tuesday.
The 17-year-old completed an installation run on wet tyres before running three more laps on the wet-weather rubber.
O’Sullivan then completed four sets of runs on slicks, beginning with five laps on a fresh set of Pirelli soft tyres.
After a break, he ran five more laps on the same set of softs before swapping to the hard compound tyre for five tours. For the last run, O’Sullivan swapped to a fresh set of the red-walled tyres.
He said: “Pretty crazy. It's a different world compared to what I'm used to in F3.
“I think especially the first install app was a big wake up call when I first went full-throttle, I got put through the back of the chassis, basically.
“But yeah, especially towards the end of the day, I kept getting on to it. Obviously, a lot of areas to build on early on with the high speed and a bit of confidence in the car.
“I mean, crazy experience, obviously, easily the fastest car I’ve driven and really enjoyed it.”
O’Sullivan last drove the circuit in July during the FIA Formula 3 round in support of the British Grand Prix, taking pole before securing second place in the feature race for Carlin.
The Briton said the braking was the main difference to the F3 car he is used to driving.
“I think, obviously, the power is crazy,” he said.
“I think in general, the balance is a lot more predictable and stable in an F3 car because in F1 they have a bit more freedom to make the car as nice as it can.
“But the main thing was the brakes. I mean, the main limitation was my neck rather than the car. But yeah, the braking is crazy.
“We were braking 15,20 metres later that I would have in F3 and coming in 80 or 90 miles an hour faster. So yeah, pretty crazy, but I'm quite happy with where I got to at least in the last run.”
O’Sullivan has not yet confirmed his plans for 2023 but is believed to be returning to F3.
