TORONTO -- In the sixth season of "MasterChef," viewers will see a new ingredient thrown into the mixture with a female judge joining Gordon Ramsay and Graham Elliot.

"I think I give off a more nurturing, supportive vibe in some places, but in other places I have to drop the hammer just like I do in any professional kitchen that I'm in," says new judge Christina Tosi, a pastry chef best known for opening Milk Bar, the sister bakery of the Momofuku restaurants founded by chef David Chang.

In Wednesday's two-hour premiere on CTV, the judges begin narrowing down a field of 40 home cooks vying for the "MasterChef" title. And they begin getting used to each other.

"There's a little bit of a feeling-out period ... of them feeling out what I'm about and what I like, what my likes and dislikes are in general, what I'm looking for, what I think is great potential in a chef, what I think a great dish is," says Tosi, 33, during an interview from New York.

"And I think also just the curiosity of, like, 'Is she going to be nice or is she going to be mean?"'

Tosi replaces Joe Bastianich, who co-owns Batali and Bastianich Hospitality Group, recently published the cookbook "Healthy Pasta," and is on Sky's "MasterChef Italia" and CNBC's "Restaurant Startup." With such a full plate, he bowed out of "MasterChef" and "MasterChef Junior."

"People are going to miss Joe and rightfully so," Tosi says.

"He's an awesome guy. He was a great judge. I think that the way that Gordon, Graham and he worked together -- in terms of how they judged, how they mentored and how they brought these home cooks along in the kitchen -- was really great and really special."

But Tosi too has an extensive resume. Since launching the first Milk Bar in 2008, five more have opened -- including one in Toronto -- and another is due to hit Washington, D.C., later this year.

She has two prestigious James Beard awards: she was named outstanding pastry chef this year and rising chef of the year in 2012. And she has written two cookbooks -- "Momofuku Milk Bar" and "Milk Bar Life," published in April. She joins "MasterChef Junior" as well.

Sweet treats might be Tosi's area of expertise, but she has no trouble offering her opinion on savoury items.

"The one thing we're reinforcing this year is: to be a good chef you have to be a great savoury chef and a great pastry chef.... To be an accomplished chef you have to be everything. And I think that's the most exciting part of this season."