Preheat oven to 350ºF.
Combine the dry ingredients in the large mixer bowl. Using the paddle attachment, add the oil, water or milk, and eggs (one at a time), scraping down bowl after each addition. Add vanilla and butter flavoring. Beat the mixture on medium high speed for 8 minutes.
In a small bowl, combine the pecans, sugar, and cinnamon.
Combine sugar, milk, butter flavoring, and vanilla. Set aside until cake is cooled and out of pan.
In a greased and floured tube or bundt pan, add layer of butter cake mixture, layer of filling alternatively until all ingredients are gone.
Bake for 45 minutes or until cake tester inserted into cake comes out clean. Cool in pan for 10 minutes. Turn out onto cake platter and cover with glaze.