Step 1

Line an 8x8 or 9x9 inch square baking pan with parchment paper.

Step 2

In a medium saucepan over medium heat, combine Nutella, butter, chocolate and powdered sweetener. Stir until melted and smooth.

Step 3

Remove from heat and stir in hazelnut flour, protein powder and chopped hazelnuts.

Step 4

Transfer to pan and press firmly and evenly into the bottom. Use a flat bottomed glass covered with parchment or plastic wrap to help press it in.

Step 5

Refrigerate until firm, at least 1 hour.

Step 6

In a heatproof bowl set over a pan of barely simmering water, combine butter or oil and chocolate chips. Stir until melted. Spread over cooled bars and refrigerate until set, about 20 minutes.