Preheat oven to 375 degrees. Mist an 8x8 baking dish with nonstick cooking spray. Combine the tofu, sour cream and lemon juice in a food processor and blend until smooth. Set aside. Heat the olio in a skillet over medium-high heat. Add the onion and cook, stirring until softened, about 5 minutes. Add the spinach and cook, stirring, until all of the water from the spinach has evaporated, about 5 minutes more. Remove from the heat and stir in the salsa, reserved tofu mixture olives and nutritional yeast flakes, if using. Transfer to the prepared baking dish and bake, uncovered, for 20 minutes or until bubbly Remove from the heat, let cook for 5 minutes and serve with chips. Per Tablespoon: 17 calories