Melt 2 tbsp vegan butter in a large frying pan. Add a diced onion and minced garlic, and sprinkle with a teaspoon of salt. Saute over medium-low heat for about 5 minutes, until the onions are translucent.
Add 1/2 cup shredded carrots and 1 1/4 cups orzo pasta, and stir well.
Pour in 2 cups of water or low-sodium vegetable broth and stir well, then bring to a slow boil.
Add 3 cups of chopped broccoli florets, stir well, then simmer until most of the liquid is absorbed.
Turn the heat to low and add 1 tsp of Dijon mustard, 1 cup plant-based milk, and 1 1/2 cups vegan cheddar. Stir until the cheese melts and forms a smooth, cheesy sauce. Add salt and freshly ground black pepper to taste.
Notes
Stir frequently and don't walk away from the orzo while cooking.
Add the broccoli earlier if you want it softer, or later if you want it crunchier.
The size of the broccoli pieces will also determine how fast they cook.
To hide the veggies more and make it more kid-friendly, chop the carrots and broccoli in a food processor until very small.