Preheat oven to 180 C / Gas 4. Line a muffin tray with 12 paper cases.
In a bowl measure out all of your ingredients for the cupcakes. Mix this for a couple of minutes until well combined.
Fill your cupcake cases and bake until a skewer comes out clean, about 20 minutes. Remove and place on a cooling rack.
For the buttercream place your butter in a mixer and mix on medium for about 8 minutes until it is white then add your lemon zest and vanilla and gradually add your icing sugar and yellow food gel, mix and making sure to scrape down the bowl.
Once all is combined put the mixer back on for a minute it should be light and whippy.
Fill a piping bag with a 2d tip and pipe your roses on or any design you wish to do.