Do you have a favorite recipe that is simple and healthy?

I’d like to add some variety to my weeknight meals. By the time I get home from work, it’s usually about 10 PM. So I want to make something in about ½ hour or less.

And if you have any favorite substitutions that make a meal healthier, I’d love to hear that too. (Like cauliflower instead of mashed potatoes as a side dish- it kind of hits the same spot.) Thanks!