Heat olive oil in large saucepan over medium heat. Add onions, smoked paprika and a pinch of salt and cook, stirring occasionally, until soft but not browned, about 10 minutes.
Add carrots, celery, fennel, winter squash and thyme, season with a little more salt and cook for another 5 minutes, stirring often.
Pour in white wine, increase heat to high and bring to a boil. Add vegetable stock, tomatoes, bay leaf, marjoram, oregano and chili flakes.
Return to a boil, add potatoes and reduce heat to medium and simmer 10 minutes.
Add orange zest and juice along with a dash of hot pepper sauce. Taste and adjust seasonings with lemon juice, salt and freshly ground pepper.