Pre-heat the oven to 350F. Oil an 8x8 square cake pan. Set aside.
In a small bowl combine the plant milk with vinegar and set aside, allowing it to curdle a little while working on next step.
Combine all dry ingredients in a large mixing bow. Add in all liquid cake ingredients, including the almond vinegar mixture, and mix everything thoroughly to combine.
In a separate bowl combine the cashew butter with the boiled water and stir to thin out and dissolve the cashew butter. Add this to the cake batter and mix everything to combine. Pour the batter into prepared cake pan.
Bake in a preheated oven for approximately 40-45 mins (until the top is nicely golden and a skewer inserted in the center of the cake comes out completely dry). Remove from oven and cool on a cooling rack completely before proceeding to frost.
While the cake is baking, prepare the frosting by combining all the ingredients except for shredded coconut in a power blender until completely smooth. Add in shredded coconut and mix once more (use the vitamix tamper to help you along, or pause to scrape sides and keep blending until the coconut is incorporated). Transfer into a glass container and refrigerate until cake is ready to be frosted (or for at least 1-2 hours to let it firm up). Once ready, frost cake, decorate with blueberries and flower petals and serve!