Grease and parchment line a 9" x 9" cake pan & preheat the oven to 350°F
First prepare the struesel topping by creaming the cold butter with both sugars - just about 2 minutes to smooth.
Add the cinnamon, salt & flour and mix just until combined
Sprinkle the topping out onto a parchment lined sheet pan & freeze until needed
Next prepare the pecan filling by combining all those ingredients into a food processor to fine consistency. Reserve.
Prepare the cake batter by combining the oil with the vegan butter together in a small sauce pot & gently melt over a medium heat.
Combine the plant milk with the vinegar ~ let stand for 5 minutes to thicken.
Add the vanilla extract to that then add the melted vegan butter & oil combination to the thickened milk mixture
Sift all the dry ingredients together in a large mixing bowl, including the sugar.
Pour the wet ingredients in & whisk to a smooth batter
Pour the batter into your prepared pan and then sprinkle the pecan filling over top
Next break up any large chunks of the struesel topping & sprinkle it over the pecan filling & the cake batter.
Bake immediately in a preheated 350°F oven for 30 minutes then turn the oven down to 300°F & bake for another 20-25 minutes or when a toothpick inserted into the center comes out clean.
Cool in the pan then serve warm!
A dusting of powdered sugar is optional!