Heat the oven to 175 C (350 F) and place a rack in the middle of the oven. Butter a loaf pan and place in the oven with a baking sheet under the pan.
In a regular sized bowl, mix together with a whisk the flour, baking soda and the salt.
In a larger bowl, mix together the sour cream, sugar, vanilla and eggs. After all is mixed together, then add the poppy seeds and then the flour mixture.
With a rubber spatula, fold the oil into the mixture. Move the batter to the pan you prepared and smooth out the top. Bake the cake for 50 to 60 minutes.
Move the pan to a cooling rack and let the cake cool for about 5 minutes. To loosen the cake from the pan, use a knife between the sides of the cake so you can remove it. Move over to a rack and let it cool.