• Tip! For perfect cookies each and every time, use a kitchen scale and weigh out the ingredients using the weight measurements provided.

Brown the butter:

• Place the butter into a medium saucepan. Melt the butter over medium heat, then continue cooking, stirring regularly until the butter starts to turn golden and smell a bit nutty. Reduce the heat under the pan slightly and continue cooking, swirling the pan continually to assess the colour and to avoid the milk solids on the bottom of the pan scorching. When the mixture changes from golden to amber, remove from heat and immediately pour into a clean bowl. Allow the browned butter to cool for 30 minutes.

Mix the dry ingredients:

• Add the oats to a blender or food processor and blend until finely ground and powder-like. Transfer the oats to a medium bowl. Add the flour, baking soda and salt and whisk to combine well. Set aside.

Mix together the dough:

• When the browned butter has cooled, (it shouldn't be hot but it's ok if it's a bit warm) add the brown sugar and white sugar. Whisk together until smooth. Add the egg, egg yolk and vanilla and whisk again until smooth.
• Add the oat-flour mixture and use a spatula to stir together just until no flour is visible. Fold in the chocolate chips.

Chill the dough (do not skip or skimp!):

• Cover and refrigerate until dough is firm enough to scoop, about 30 minutes.

Refrigerate the dough balls (do not skip or skimp!):

• Line baking sheet with parchment. Divide dough into 55g (3 Tbsp) mounds and place on the baking sheet. Cover the dough a chill in the refrigerator until completely firm, at least 1 hour or up to 48 hours.

Bake the cookies:

• Preheat oven 350F (non-convection) Transfer 6 portions of the cookie dough from the refrigerator to a large parchment-lined baking sheet. Space them well apart as they will spread. (4 inches between dough balls is ideal.)
• Bake in the preheated oven for 12-14 minutes. The cookies will look a little undercooked at that time, but trust that they will continue to cook on the pan and don't over-bake. (13 minutes is perfect in my oven for crispy around the edges and chewy in the centre. You could bake the extra minute if you prefer crispier cookies). Cool the cookies on the baking pan for 5 minutes then transfer them to a cooling rack. **If baking multiple batches allow the baking sheet to cool completely between batches.
• The dough balls can be refrigerated for up to 48 hours or can be frozen for up to 3 months. If baking from frozen allow a bit more baking time.