Preheat the oven to 325°F. Generously grease a 10-inch bundt pan with dairy free butter and dust it with flour, tapping out the excess.Stir the almond milk and lemon juice together in a measuring cup and set aside for 5 minutes.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large bowl, beat the butter and sugar on medium-high speed for 4 minutes, until pale and fluffy. Add the eggs one at a time, beating well after each, then beat in the vanilla.
With the mixer on low, add the flour mixture in three additions, alternating with the almond milk mixture, beginning and ending with the flour. Mix just until combined, then spoon the batter into the pan and smooth the top.
Bake for 55 to 65 minutes, until golden and a long skewer inserted in the center comes out clean.
When the cake is almost done, melt the butter with the sugar and water in a small saucepan over medium heat, stirring until the sugar dissolves completely.Do not let the sauce boil hard. Remove it from the heat and stir in the vanilla.
Leave the hot cake in the pan and poke holes all over it with a long skewer. Slowly pour the warm butter sauce over the cake and down the sides, letting it soak in as you go, then let the cake cool completely in the pan, about 2 hours.
Invert the cake onto a serving plate and slice. The sauce creates a sweet, crackly outer crust while keeping the inside incredibly moist and tender.