This coffee cake is truly one of my favorites, and no one ever guesses that it's gluten-free and vegan. It's delicious with add-ins, such as blueberries, chocolate chips, raspberries, sliced nectarine, apple, peach or pear.
Preheat oven to 350°F. Grease and line a 7 x 11-inch glass Pyrex baking dish or a 9-inch round metal baking pan.
Cake: In a large bowl or bowl of a stand mixer, combine the cake mix, milk, oil and vanilla, beating until smooth. Stir in blueberries, if using.
Topping: In a small bowl, mix together the brown sugar and cinnamon. Set aside.
Pour half of the batter into the prepared baking dish. Sprinkle with half of the brown sugar mixture. Drizzle the rest of the cake batter on top. Top with the remaining brown sugar mixture. Bake the cake about 60 minutes, or until a tester inserted into the cake comes out clean. Let cake cool completely before serving.
Sometimes I find that I need to bake the coffee cake for an additional 5 minutes or so.
If using a glass Pyrex pan, make sure to set the hot cake on a trivet or rack when you pull it out of the oven. Sometimes the glass dishes can shatter if placed on a cold tile or stone counter.
Recipe by Julie's Original at https://juliesoriginal.com/cinnamon-coffee-cake-gluten-free-vegan/