Whisk the nondairy milk and vinegar and set aside for five minutes.
Cream together the sugar and "butter" in a stand mixer or hand mixer fitted with a wisk, until light and fluffy, about 2-3 minutes. Stop the mixer and scrape down the bottom and sides of bowl a couple of times during the mixing.
Mix the lemon juice, zest, vanilla extract and milk-vinegar mixture.
Sift into a bowl the flour, salt, baking soda, and baking powder
Add the flour to the butter and sugar mixture in three batches, alternating with the almond milk mixture. Mix for 20 seconds after each addition, then scrape down the sides of the bowl to ensure everything's integrated.
Add the poppy seeds and mix with a spatula to disperse them evenly through the batter.
Oil and flour a bundt cake pan. Pour the cake batter into the pan and bake in a preheated 350-degree oven for 45 minutes or until a toothpick inserted in the cake comes out dry. Let the cake stand in the bundt pan on a rack for 10 minutes, then unmold. This cake unmolds easily, but if you need help run a knife lightly and carefully around the edges.