Cook the macaroni according to the directions on the package and drain well.
Meanwhile, cut the cauliflower into small pieces, then steam for about 10 minutes, or until soft.
Add the cauliflower to a blender, along with the milk, cheese, butter and salt. Blend until smooth.
Pour the sauce over the macaroni while it’s still hot, and stir until evenly coated.
Serve immediately. Or, if you’re meal prepping for your toddler, add the mac and cheese to silicone cupcake liners. Store in the refrigerator for up to 5 days. Or, to freeze, line them on a sheet pan and place them in the freezer until frozen solid. Then, place them in a freezer bag and store them in the freezer for up to 3 months.