To make the ranch tzatziki dressing: In a bowl, whisk together the milk, yogurt and Hidden Valley Original Ranch Greek Yogurt Salad Dressing Mix. Stir in the cucumber and mint, cover and chill in the refrigerator for 30 minutes to thicken.
Preheat the oven to 425 degrees F. Line a baking tray with parchment paper and lightly butter the parchment. Set aside.
Toss the zucchini with kosher salt and place in a sieve over a bowl for 10 minutes. Squeeze any excess liquid through the sieve, then place in a clean dishcloth and squeeze more liquid out. Transfer the zucchini into a medium bowl and combine with the egg, Parmesan cheese, flour, breadcrumbs, garlic, onion and basil. Season with salt and pepper.
Using an ice cream scoop or large spoon, place about 2 tablespoon-sized scoops onto the parchment-lined baking sheet. Lightly press until it is a disk, about 1/2 inch thick and 3 inches in width.
Place in oven and bake for about 10 minutes, then flip and bake for another 5-10 minutes, until it is golden brown and cooked through.