Make the reduced strawberry puree: Rinse and hull the strawberries. Using a food processor or blender, puree them. Pour the puree into a small pot and simmer for 25-30 minutes, until it reduces to about 1/2 cup. You might have a little more than that; save for topping ice cream or waffles. Allow it to cool for a few minutes before adding to cake batter.
Preheat the oven to 350 degrees F and prepare 2 8-inch round cake pans by lining the bottom with a circle of parchment paper and spraying with oil.
Make the Vegan Buttermilk: Combine the non-dairy milk and apple cider vinegar. Stir a little, then set aside.
Using an electric hand mixer or a stand mixer, cream together the softened butter, canola oil and sugar until creamy. Mix in the vanilla.
In a separate bowl, whisk together the flour, baking powder and salt.
Using the mixer on low speed, alternate adding the flour mixture and vegan buttermilk, mixing until just combined each time. Now add in the reduced strawberry puree with the mixer on low.
Pour the cake batter evenly into the prepared pans, and bake for 30-35 minutes, until the edges are golden brown, the surface looks and feels set and a toothpick inserted comes out mostly clean with no wet batter.
Allow the cakes to cool in the pans for 15 minutes, then carefully invert them onto a cooling rack. Allow them to cool completely before frosting. You can place them in the refrigerator to speed the cooling process along if you need to.
For the Strawberry Frosting:
Using a food processor or blender, blend the freeze dried strawberries into a powder. Set aside.
Using your hand mixer or stand mixer, beat the vegan butter and shortening together until creamy. Gradually add the powdered sugar, 1/2 cup at a time, until all the powdered sugar is mixed in.
Now add in the strawberry powder and mix in. With the mixer on low speed, add in the vanilla and 2-3 tablespoons of soy milk as needed to thin the frosting to a desirable consistency. If it gets too thin, add more powdered sugar. If it's too thick, add more milk until it's just right.
Once the cakes are completely cooled, frost and enjoy!
If you want your cakes to be pink like the frosting, you can add a tiny drop or two or pink food coloring (find a vegan friendly brand, Whole Foods has some options).
You can substitute any plant based milk for the soy milk.
You can also make this cake as a 9 by 13 inch cake. It will need to bake more like 40-45 minutes though. Or to make cupcakes, fill liners 2/3 of the way full and bake for 20-25 minutes.
Store leftover pieces of cake in the refrigerator, covered for 4-5 days. The cakes can be made ahead of time and stored in the refrigerator, covered in plastic wrap, until ready to frost. The frosting can also be prepared ahead of time, a day or two, and store in the refrigerator. When ready to use, let it come to room temperature and then give it a good stir.
Frosted cake pieces can also be frozen, wrapped well or in a freezer friendly container.