A: When it involves rendered bacon fat.
Here's a pretty simple salad with a balsamic vinaigrette. (Thank you firefox spell check for telling me I don't know how to spell vinegarette.)
1 bag mixed field greens
3 slices thick cut bacon
1 package white button mushrooms, sliced.
some goat cheese
Cut the bacon into ~1/2" pieces. Cook in heavy cast iron pan (is there any other kind?). Scoop out the bacon and drain on a paper towel. Sautee the mushrooms in the hot bacon fat. Scoop these out and set aside with the bacon when they're done.
Combine all the dressing ingredients and whisk together. Dress the salad. Toss the salad. Add the bacon, mushrooms, and goat cheese. Toss again. Serve.