Preheat oven to 350 degrees. Lightly grease 5 silicone Twinkie molds
In a large mixer bowl sift or whisk together the dry ingredients until no lumps are in the dry ingredients.
Add the eggs. Beat on low 10 seconds to moisten the dry ingredients. Increase speed to medium. Beat on medium 30 seconds or until fully combined
Scrape down the sides of the bowl. Add the butter and the milk. Beat on low 10 seconds then increase speed to medium. Beat on medium 30 seconds or until fully combined and smooth
Scrape down sides of the bowl again. Add the sour cream and the vanilla. Beat on low 10 seconds then increase speed to medium. Beat on medium 30 seconds or until fully combined and you have a thick smooth batter
Scrape down the sides of the bowl and push the batter to the center of the bowl
Divide the batter evenly among the prepared Twinkie molds. Use finger or a small spatula and smooth the tops out for an even bake
Place the molds on a baking sheet. Place in the preheated oven and bake at 350 degrees for 13-15 minutes or until golden and a tester comes out clean
Remove from the oven. They will be soft but will firm up as they cool. Allow to cool on the pan about 30 minutes or until the cakes are firm enough to transfer to a wire rack
Remove from the molds and place on wire rack. Allow to cool completely before filing