Preheat the oven to 350℉ & grease & parchment line 2-8" cake pans
If you are making the toffee recipe it is a good idea to do that ahead of time, although it can be done quickly while the cake is baking
In a large mixing bowl combine the dry ingredients (the flour, salt & baking soda) including the sugar, whisk to combine well or sift together
In a small sauce pot warm the plant milk with the instant coffee granules just enough to dissolve them. Remove from the heat & add the vinegar & let stand to thick 5 minutes (soy milk is the only plant milk that will thicken but you can use any milk you prefer)
Pour all the wet ingredients (the milk /coffee mixture along with the oil & vanilla extract) into the dry ingredients in the bowl & whisk to develop the batter *approx 30 strokes
Divide the batter between your prepared cake pans and bake immediately for 30- 35 minutes or until springy to the touch when you gently press the centers
Cool in the pans until you can safely touch them without burning your self then flip them out onto a cooling rack to cool to cold
Prepare the buttercream recipe according to the instructions on that post & add the coffee liquor last
Fill and ice the cake as shown in the video