Preheat oven to 375 degrees.
Remove stems and place mushrooms on baking sheet or in large baking dish.
In food processor, finely dice broccoli and carrots until you have about ¾ a cup of each and the texture resembles around the size of rice or quinoa.
In a large mixing bowl, add your veggies along with chopped green onions. Add cheese, bread crumbs, melted butter, and salt. Stir to combine. Taste to see if you need to add more salt.
I find that my hands work best for stuffing the mushrooms, but you could also use a small spoon. Stuff until they have a nice sized mound on top.
Place in oven and bake for 25 minutes.