Welcome to the Cake Decorators Q&A

How do i get the champagne flavor in to the dough and buttercream

Hi BBieber

To get the champagne flavour into the cake you will need to replace any liquid which your recipe uses with the alcohol. The flavour becomes infused into the batter as the champagne reduces during the baking process. Alternatively you could use a good oil based food flavour which would not interfer with the consistency of your batter or cream. LorAnne oil make white wine/champagne flavour as seen here:
http://www.thecakedecoratingcompany.co.uk/sparkling-wine-formerly-champagne-lorann-oils-1-dram-food-flavouring-oils

For scratch recipes google ‘champagne flavoured cake and buttercream recipes’.

Hope this helps.