Remove from heat and mix with the hazelnut butter until well combined.
Let it cool at room temperature for a few minutes and place the bowl in the refrigerator for at least 2 hours. Once it is firm, remove from the refrigerator and let sit at room temperature, the hazelnut butter will become a little bit softer and easier to work with.
Add the rolled oats, oat flour and protein powder to the bowl of a food processor. Process for 3-5 seconds, or until the oats are roughly chopped. Transfer to a mixing bowl.
In a small pan, combine the brown rice syrup, coconut sugar, and almond butter. Heat on medium heat until everything is well combined and the sugar is dissolved.
Pour the brown rice mixture over the oats and protein powder. Stir in the vanilla extract and mix using a wooden spoon or spatula until you get a soft and sticky dough.
Add the rice crisps and mix until they are well incorporated. Do not overmix to keep the crunchy texture.
Place the dough between two sheets of parchment paper and roll it using a pastry roller. You want to have a really thin layer of dough.
Cut the dough into 12 rectangles of about 4×2 inches.
Using your hands, form a small log with the chocolate hazelnut butter (about 1 tbsp). Be careful, if your kitchen is too hot, the hazelnut butter will be really soft. I recommend you keep the chocolate hazelnut butter in your refrigerator if it is the case.
Add the chocolate hazelnut butter log on top of a rectangle, leaving about 1/4-inch on the sides. Top with another rectangle of dough.
Carefully press the sides to close bar. Repeat with the next 5 bars.
Place in the refrigerator for at least 1 hour.
The bars will keep at room temperature, or in the refrigerator if it’s too hot outside.