。
She heaped a mountain of salad onto her plate.
Literal
She [topic-は] salad [object-を] mountain [like-のように] plate [object-を] took.
An unusual sentence with two を particles in a single clause — Japanese normally avoids this 'double を' clash, since two of them in the same clause feel awkward. The likely intent is 'she took/served salad onto a plate, piled like a mountain': サラダ ('salad') is what's being heaped, 山のように ('like a mountain') describes the heaping, and 皿 ('plate') is what gets the salad. A more natural phrasing would split the actions or use 皿に ('onto the plate') for the destination. The image is unmistakable regardless: a plate piled high with salad. 山のように is a stock simile for towering quantity.