Preheat oven to 375°. Heat a 12 inch oven-safe skillet over medium-high heat.
Add in ground beef, onion and garlic. Break up the beef while stirring occasionally until the beef is browned and the onion is translucent, about 8 to 10 minutes.
Stir in tomatoes, Worcestershire, rosemary, 1 tablespoon of parsley, pepper and 1/2 teaspoon of salt.
In a small bowl, whisk the flour into the beef broth. Once combined, add into the skillet. Reduce heat to medium-low and cook, stirring often, until thickened, about 15 minutes.
Place cauliflower and water in a large saucepan and bring to a boil over high heat. Once boiling, cover and reduce to medium-high heat. Cook until the cauliflower is tender, about 10 minutes.
Drain cauliflower, then add butter, heavy cream and salt to taste. Mash with a potato masher or fork until smooth. Spoon cauliflower mash evenly over the skillet mixture.
Bake until the top starts to become light golden brown, anout 20 to 25 minutes.
