Heat your oven to 350°F/180°C. Line a baking sheet with parchment paper. Once you have prepped your ingredients, keep a small handful of both the chocolate chips and the mini eggs to the side.
In a small saucepan over medium-low heat, melt the butter. Once melted, increase the heat to medium and let the butter begin to foam. Keep cooking and stirring with a spatula, until the butter begins to brown and gives off a nutty smell (2-3 minutes). Pour into a large bowl, making sure you scrape out all of the brown butter stuck at the bottom of the pan. Let cool.
1 ½ sticks butter
Add the sugars, salt, and vanilla extract and whisk until smooth. Add the egg and the egg yolk, and beat until the batter is smooth and thick.
1 cup light brown sugar, ½ cup sugar, 1 teaspoon kosher salt, 2 teaspoons vanilla extract, 1 large egg, 1 large egg yolk
Add in the flour, baking soda and baking powder. Fold everything with a rubber spatula until combined. Stir in the chocolate chips and chopped mini eggs.
2 ½ cups all purpose flour, ½ teaspoon baking soda, ¾ teaspoon baking powder, ⅔ cup chocolate chips, ⅔ cup mini eggs
Scoop out 3 tablespoons of cookie dough and roll into a ball, place on the prepared baking sheet. You'll bake 6 cookies at a time. On top of each cookie dough ball, press in the extra chocolate chips and mini eggs.
Bake for 10-12 minutes for soft cookies, a minute or two longer if you want them crispier. Allow the cookies to cool on the baking sheet for 10 minutes before removing to a wire cooling rack to cool completely.
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. Crushing Mini Eggs:I recommend putting the mini eggs into a ziplock bag, and smashing them with a rolling pin rather than chopping them with a knife. Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt. Please note I am using Diamond Crystal Kosher Salt and not Morton Salt, which is a coarse kosher salt. Coarse kosher salt is much too salty for this recipeStorage: keep the baked cookies in a tupperware for up to 1 week at room temperature. Freeze unbaked cookie dough balls for up to 2 months. When ready to bake, take them out of the freezer and bake at the same temperature as above but for an extra minute or two.