@Background Pony #941B  
Suspension of Disbelief for plot or mechanics of a fictional world has to do with the details being paid attention to and justified to be made believable (or) exaggerated humorously (or) with a lampshade by the creators. It becomes more believable under circumstances in which they are explained.
 
I’m under the impression magic in Equestria is related to a manipulation of dark matter/dark energy manipulation of mass (Pegasi wings) and energy conversion (horn).
 
This would explain how Fluttershy can be caught falling by a group of butterflies, Pegasi can walk on and move clouds, Unicorns can create levitation/telekinesis, energy blasts, and Earth ponies have it in strength and unnatural dexterity, up to and including breaking of the space-time continuum (i.e. Pinkie Pie).

I’ve always assumed that they normally do stuff like that by using the Magic of Suspension of Disbelief. As long as they can justifiably claim to have the knowledge or innate talent to accomplish something, the ability to do that thing is necessary for pony society to exist, and no one is paying any particular attention to the details, they can carry out tasks that should be physically impossible.
 
Like all other forms of magic it’s significantly weaker on Earth, and many ponies have never really adjusted to that.

It slices! It dices! It makes mounds of delicious julienne fries! How much would you pay? But wait! There’s more! Order now and get this non-stick frying pan, absolutely free!

@Otterhand  

 
Followed by an explosion and a burning kitchen.

@laofuzi  
Oh, now I GOTTA do it. I have to.

She could also use the manual Food Chopper product too  

As seen on TV!

@ObliviaTheChangeling  
“HUMAN POLICE OPEN THE DOOR!”  
“Mmmh mmmh mmmh mmmh?” (“Can’t a mare make a salad?”)  
[Loud electric knife noises!]

Oh, that Brownie

@Otterhand  

imagine that turning around with red splats all over her.(most likely caused by slicing tomatoes)

@Meanlucario  
Assuming they all have to use knives like this, I can’t imagine any other earth pony can get good precision with this thing.
 
I dunno, maybe Brownie just has a weak jaw. :V

@Dragonpone  
No, just Brownie.

Unicorns and pegasi must be really bad at cooking.

I love horse wife.