Preheat your oven to 350 degrees and spray a baking sheet with cooking spray.
Season the chicken with salt and pepper and bake until no longer pink inside, about 25-30 minutes.
Combine the water and broth in a large pot and bring to a boil. Once boiling, add in the cauliflower, cover and took until fork tender, about 10 minutes.
Heat the olive oil up in a large pan on medium high heat. Add in the onion and garlic and cook until tender and golden brown. Transfer into a food processor.
Once cooked, use a slotted spoon to transfer the cauliflower into the food processor. Add 2 Tbsp of the cooking liquid and puree until smooth, stopping to scrape down the sides as necessary.
Cook the Mac & Cheese according to package directions in the microwave. Peel back the plastic covering and divide the cauliflower mixture between the two trays, stirring in until well mixed. Season liberally with salt, tasting as you add it.
Divide the Mac & Cheese between 6, 3-cup lunch containers. Slice the chicken and divide between the containers. Finally, add some baby carrots to each container.
Cover and refrigerate until ready to serve - up to 5 days.