Beat butter, sugar and vanilla in a large bowl with mixer on high 3 minutes or until fluffy.
Add eggs, 1 at a time, beating well after each.
Sift flour with baking soda to mix well.
On low speed, beat in flour in 3 additions, alternately with milk, in 2 additions (beginning & ending with flour), just until blended, scraping sides of bowl as needed.
Baking at 350 degrees works well. Should take approximately 25 to 35 minutes. Bake 'til toothpick in center comes out clean. Be sure to check, as time is strictly approximate. And after it begins to brown, will continue cooking in middle without over-browning.
Elora's Notes: Because original recipe calls for regular milk, might need to add 1 or 2 tablespoons milk. O.k. if batter is quite thick. We do NOT add extra milk, and it turns out PERFECT. Emmett used this recipe to make an upside down Peach cake in a 10-inch iron skillet with it and it was LUSCIOUS! But it ran ALL OVER the oven and we had AT LEAST 1/4 cup batter left in the bowl! So, we aren't sure HOW MUCH it makes. But I figure AT LEAST three 9-in. pans, or a 10 X 14 inches sheet pan, or more than likely three 9-in. pans PLUS one 8-in. pan. I figure you make the three 9-in. layers & the one 8-in. layer. Though it MIGHT NOT be more than enough for three 9-inch pans. If it is, cut the 8-in. layer in half & freeze for unexpected company or when you want a cake & don't want to take time to make one. Can frost it either before freezing or after thawing.