Gather all your ingredients together, including the kitchen tools (bowls and pot) that you’ll need.
Cut your butter into chunks and place into your pot. Using a medium flame, start to brown your butter. The whole process should take about 5 minutes (maybe a minute or two longer…just keep your eye on it). When your butter begins melting, you should see it start to foam; be sure to keep whisking or stirring. After a few minutes, you should begin to see tiny brown bits of butter gathering at the bottom of the pot. Keep whisking until the butter gets a bit darker, being careful not to burn it. At about the 5 minute mark, your butter should be browned. If unsure, keep it on the heat a minute or two longer. Once done, remove from heat and let it cool for a few minutes (don’t let the butter harden).Creaming your butter instead? Place softened, room temperature butter into your mixer fitted with a paddle attachment and follow the remainder of the recipe using your mixer; just stir in the candies and chocolate chips by hand. Place both the brown and granulated sugar into a medium-sized bowl and add the cooled brown butter, including all the brown bits on the bottom of the pot (those brown bits add flavor!). Mix together with your spatula.
Add in your vanilla.
Add in your eggs, one at a time. Scrape down the bowl and set it aside.
Using your large bowl, sift (or whisk) the flour, cornstarch, baking soda and salt. This ensures there are no lumps of flour and that all other dry ingredients are incorporated throughout.
Pour the wet ingredients into the flour mixture and stir together.
Add the robin egg pieces and chocolate chips; stir together until the cookie dough comes together, as the dough starts out slightly dry but once mixed well, it comes together nicely (and may be a little “greasy” looking, which is ok!).
Line a cookie sheet with parchment and scoop out your cookie dough into balls. I scooped my cookies into 1-½ ounce balls.
Place onto the cookie sheet, cover with saran wrap and chill the dough for about 2 hours. Chilling the dough prevents the cookies from spreading too much when baking.