Place zucchini and squash on doubled-up paper towels, sprinkle lightly with salt and let sit 10 minutes. Use more towels to soak up the liquid that comes from the veggies, I will even ring them out with additional towels if there is a lot of liquid. Set aside.
In a large skillet over medium-high heat, add 1 tablespoon of the butter. Add the zucchini and squash to the pan and cook for 5 minutes, tossing often. Take out of pan and place on a plate. Set aside.
Add another 1 tablespoon of the butter over medium heat in the same pan. Add in the onion and carrot, cook until the onion is translucent about 4 minutes. Add in the broccoli, 2 tablespoons of water, cover and let steam over medium-low heat for 3-4 minutes until bright green. Take out of the pan, add to plate with the zucchini.
Add the remaining butter to the pan over medium heat. Add the garlic and cook until fragrant, about 1 minute. Add in the flour and stir into the butter, cook for 30 seconds. Add the white wine, stock, milk, and cheese. Stir until combined. Add the veggies back to the pan and using tongs, toss veggies in the sauce. Add in the frozen peas, stir in. Tear in the basil, stir and allow to wilt, taste and adjust seasoning, serve.