Preheat the oven to 350°F (175°C).

In a mixing bowl, combine the gluten-free flour, sugar, baking powder, and salt.

In another bowl, whisk together the milk, melted butter, eggs, and vanilla extract.

Pour the wet ingredients into the dry ingredients and mix until just combined.

In a separate bowl, mix the cinnamon, brown sugar, and chopped nuts for the topping.

Pour half of the batter into a greased baking pan, sprinkle half of the topping, then add the remaining batter and top with the rest of the topping.

Bake for 30-35 minutes or until a toothpick comes out clean.