Preheat oven to 425° and line baking sheet with aluminum foil for easier clean up.
Add 7 slices of bacon (or more if desired) and cook for about 10 minutes until crispy, remove from oven and let bacon cool on plate lined with a paper towel.
To prepare cauliflower, remove stem from cauliflower head and cut into florets. Or use prepared bag of cauliflower florets or riced.
Saute' cauliflower with olive oil and shallots for about 5-7 minutes, until cauliflower has softened and shallots are translucent.
Remove from heat and add to food processor to puree. Set aside.
Quarter potatoes and place in pot of water and then bring to a boil. Boil for 20-25 minutes or until knife can easily pierce potato. Drain water.
Melt butter in pot. Add potatoes and mash. Gradually add milk and yogurt. Fold in cauliflower puree. Add scallions, cheese, salt and pepper. Top with chopped bacon bits and serve.
Making in advance, transfer to baking dish and reheat in oven at 400° for 20 minutes or until top is golden.