Preheat oven to 450 F.
Cook and crumble the bacon. Set to the side. Save 4 tbsp bacon fat.
Toss cauliflower florets with 2 tbsp reserved bacon fat, salt & pepper. Spread cauliflower onto a baking sheet with parchment paper. Bake on the top rack for 14-16 minutes until tender and golden brown.
Meanwhile, heat a large pot with the last 2 tbsp of reserved bacon fat over medium heat. Add the onions and garlic, stirring occasionally for 2 minutes, or until the onions have softened.
Add the potatoes, chicken broth, parsley flakes, and salt & pepper to the same pot. Bring to a simmer over high. Once simmering, reduce to the heat to medium. Cover and cook stirring occasionally, until the potatoes are fork tender (about 10-15 minutes).
Add half of the roasted cauliflower to the pot. Mash the chowder until the desired consistency is reached. Add the cheese, cream and remaining cauliflower to the pot. Bring to a bowl, reduce heat, and let simmer for 2-3 minutes until the chowder has thickened and the cheese has melted. If the chowder becomes too thick, add some water 1/4 cup at a time until the desired thickness is reached.
Season with salt & pepper.
Divide chowder between bowls. Garnish with bacon, chives, sunflower seeds, and pumpkin seeds on top. Serve immediately!