Separate eggs, put whites in a grease free bowl and whisk until doubled in size. Add half the sugar and the cream of terter and keep whisking until combined white and thick. Feed in remaining sugar.
Put in a piping bag and pipe into greaseproof paper.
Place in a low oven 230-250 degrees for 50 minutes.
Meanwhile place the mascarpone, sugar and lime zest and juice into a bowl. combine by hand. Refrigerate to allow flavor to blossom.
When everything is cool, pipe mascarpone into the nests. Place a raspberry on top, dust with icing sugar. Serve and enjoy.