Using a pressure cooker or instant pot, steam the opo squash and red bell pepper at the same time. (If you do not have a pressure cooker, steam the squash and bell pepper in your preferred method. Alternatively you could add them to the red potatoes step and cook them all together in the pot.)
Continue onto the next step while they are cooking.
In a large non-stick pot, heat the salted butter (or vegetable oil) on medium heat.
Add the garlic and onions and cook until fragrant and the onions start to become translucent (a few minutes).
Add the diced potatoes to the pot and combine with the onions and garlic.
Add the vegetable broth and some salt, pepper, and dried thyme. Cover and reduce the heat. Simmer until the potatoes are very tender (~20 minutes). Make sure you add enough broth so that the potatoes don’t burn.
Once the potatoes are very tender, use a hand blender to puree everything in the pot. Thin the soup with additional stock if it is too thick (most likely you will NOT need any additional stock).
Add fresh lemon juice, salt, and pepper to taste.
Serve hot with some toasted french bread on the side!
If you do not have a pressure cooker or instant pot to cook the Opo squash and red bell pepper, add them into the pot with the potatoes. If you choose to cook all the vegetables in this method, you MAY need to add more vegetable broth to keep the vegetables from burning and to keep the soup from getting too thick.