1. In a large pan over medium heat, sauté the garlic in butter for 1 min then add the leeks; sauté for 2-3 mins then add the zucchini and sauté for 2-3 more mins.
2. Add the frozen chopped spinach, frozen chopped broccoli, salt, pepper, and oregano; sauté until veggies are tender and most of the liquid has evaporated; set aside.
3. In a pot over medium heat, melt the butter and then add the flour; cook the flour whisking constantly for 1 minute and then start gradually pouring in the milk 1/2 cup at a time, whisking so that the milk gets fully incorporated before adding more.
4. Once all of the milk is added, turn heat up to medium high and continue whisking until the white sauce starts to bubble and has thickened slightly, then add the kosher salt, pepper, nutmeg, cayenne, and parmesan; turn off the heat; preheat oven to 375°F.
Note: The full recipe instructions are continued in the comments of the original post and are not fully available here.
