Preheat the oven to 375ºF and line a baking sheet with parchment paper.
Add the softened butter, brown sugar, and white sugar to the bowl of a stand mixer fitted with the paddle attachment, OR use a large bowl with an electric mixer.
Beat the butter and sugar mixture until light, fluffy, and well combined. About 2-3 minutes.
Add in the eggs and vanilla extract and beat again until smooth and creamy. Scrape down the sides of the bowl as necessary. Set aside.
Add the flour, baking soda, and salt to a separate medium bowl and whisk until combined.
Transfer the flour mixture to the sugar and butter mixture, and mix it on low just until combined with no dry flour bits remaining.
Finally, add the crushed mini eggs and fold them in gently with a silicone spatula.
Use a medium-sized cookie scoop or a heaping tablespoon to drop mounds of cookie dough onto the prepared baking sheet, about 2” apart, working in batches.
Place the baking sheet in the oven and bake for 10-12 minutes, or until the very edges are turning golden brown.
Remove the cookies from the oven and immediately press in a few whole (or chopped) Mini egg pieces into the hot cookies (if desired).
Allow the cookies to cool for 5-10 minutes on the baking sheet before transferring them to a wire cooling rack.
Repeat with the remaining cookie dough.
Allow the cookies to cool to room temperature before packing and storing.