Hazelnut Succes

• 6 egg whites
• 5 egg yolks
• 1 5/8 hazelnut praline
• 1 egg
• 600 gr granulated sugar
• 240 ml water
• 200 gr confectioners sugar
• 190 gr butter (unsalted)
• 170 gr hazelnuts
• 1 ml cream of tartar