Add 1 cup of water to the pressure cooker pot. Place only the carrots into the water. Place a collapsible steamer basket on top of the carrots. Add broccoli and cauliflower.
While the vegetables cook, whisk to combine cream cheese, milk, lemon zest, garlic powder, oregano, parsley, basil, salt, onion powder, black pepper, and thyme in a small bowl. Set aside.