Preheat oven to 400 degrees F. Lightly grease a 2 quart casserole dish with nonstick cooking spray and set aside.
Dice bacon into 1/2-inch pieces and cook over medium-high heat til crisp. Remove bacon from the grease with a slotted spoon and allow to drain on a paper towel lined plate.
In a large bowl, combine spinach, cream cheese, 1 1/2 cups of the grated Mozzarella, cooked bacon, mayonnaise, tomato, garlic and Ranch dressing powder. Using a rubber spatula, mix until well combined. Scrape mixture into the prepared dish and smooth the top. Sprinkle the top with the remaining half cup of Mozzarella
Bake for 20-25 minutes or until bubbly and golden. Serve with a sliced baguette or crackers.