Preheat your oven to 350F and grease a cake pan.
Make the streusel by adding the cinnamon and brown sugar alternative to a bowl. Mix and leave to one side.
Grab a bowl and add the following ingredients: oil, milk, eggs, and vanilla extract. In a separate bowl, add the stevia, salt, flour, and baking powder.
Add the wet and dry ingredients together and mix until well combined.
Add half of the batter to your prepared pan and then add around 1/2 of the streusel you made in step one. Add the second half of the batter and top and then top with the remaining streusel.
Pour the butter over the top and then bake in the center of your preheated oven for around 35-40 minutes.
Slice, serve, and enjoy!