Combine peanut butter, hazelnut spread and honey in a large microwaveable bowl.

Microwave for about 15 seconds.

Add oats, flaxseed and walnuts to peanut butter mixture. Stir until well combined.

Line a 8 x 8 inch or 9 x 9 inch baking pan with parchment paper and add mixture to pan. Spread evenly using a spatula.

Freeze for at least 30 minutes.

Cut into full-size or bite-size bars.