Preheat the oven to 350 degrees F. Spray a 9-inch springform pan with nonstick cooking spray.
For the “crust” mix together gluten-free flour blend, xanthan gum (if needed), flaxseed, sugar substitute, salt and baking powder in a large bowl. Add milk, oil and egg to dry ingredients and use a spatula to mix until smooth. Scrape the mixture into the prepared pan and spread around evenly.
For “filling,” beat the Neufchatel cheese until smooth. Beat in the yogurt, butter, vanilla and sugar. Spread over the cake mixture. Place springform pan on a rimmed baking sheet (in case of leakage) and bake on center rack for 40 to 45 minutes. Remove from oven with filing is mostly set, but center still looks a little gooey.
To serve, remove side of springform pan and dust with powdered sugar. Serve with preferred toppings, recommendations include berries, candied nuts, caramel sauce or fruit preserves and syrups.