Root Vegetable Soup

Name: Root Vegetable Soup
Ingredients: 2 tbsp olive oil; 1 large yellow or white onion (diced); 3 cloves garlic (minced); 3 1/2 cups vegetable broth; 1 head cauliflower (cut into small florets (12 oz of florets)); 2 carrots (peeled and cubed (6oz / about 1 1/2 cups)); 1 large turnip ((6oz / about 1 1/2 cups)); 1 large parsnip (peeled and cubed (4oz / about 1 cup)); 1 tbsp prepared horseradish; 1 1/2 tsp mustard powder; 1 tsp dried thyme; 1/2 tsp black pepper; 1/2 tsp fennel seed (crushed or roughly chopped); 1/8 tsp celery seed