Lemon Curd: Add all the ingredients in the Lemon Curd section into a small pot or saucepan. Turn the stove to medium heat and whisk everything together fully. Keep mixing it for about 15 minutes as it heats up and thickens, then remove from heat and pour immediately into a large heat proof bowl. Let it cool at room temperature for 20-30 minutes, then move to the fridge. It will take about 2 hours to fully cool.

Cake Layers: Pre-heat the oven to 350°F and grease 3 8-inch cake tins and line with parchment rounds. Add the flour, sugar, baking powder, and salt into a large bowl and mix together. Then add in the non-dairy milk, neutral oil, and vanilla extract, then fully mix until just combined. Finally add in lemon zest and blueberries and fold throughout gently. Pour the batter evenly into the cake tins and bake for 30-35 minutes.

Buttercream Frosting: Take the vegan butter directly from the fridge and put into a large mixing bowl. Use a mixer to beat the butter until it is soft and fluffy, then add in the vanilla extract and add the powdered sugar one cup at a time, mixing and scraping down the sides of the bowl as you go.

Build the Cake: Add frosting to the tops of two of the three layers, then pipe a ring of frosting around the top of the cake. Put each back into the fridge for a few minutes to let the frosting harden a bit, then scoop lemon curd onto the top of each layer and smooth with a spatula. Once those layers are ready, gently put one on top of the other, then put the final layer on top of those. Finish frosting the top and sides of the cake, and decorate as desired.