Prepare the Sponge: Mix the dry ingredients (self-raising flour, salt, sugar) and wet ingredients (vegan milk, olive oil, lemon zest, vegan honey, vegan yogurt) separately before combining them gently until the batter comes together. Add the yogurt with the rest of the wet ingredients if the batter is too thick.
Bake the Cake: Divide the batter into three separate cake tins and bake for about 20-25 minutes at 350°F (175°C) or until golden brown.
Make the Lemon Vegan Honey Syrup: Simmer vegan honey, lemon juice, water, and lemon zest for a few minutes and leave to cool.
Assemble the Cake: Brush each cooled cake layer with the lemon vegan honey syrup. For the filling, pipe a spiral of vegan buttercream on the first cake layer, leaving gaps to fill with raspberry conserve. Repeat with the next layer, then cover the top of the cake with the rest of the buttercream. Decorate with fresh raspberries and basil leaves.