In a small saucepan set over medium heat, brown the butter. Stir the butter occasionally until it turns amber in color and develops little brown specks.

Transfer the brown butter to a medium-sized mixing bowl and set it in the freezer for 5 minutes to chill. Aim for at least 90g of brown butter.

Once the butter has cooled down slightly, whisk in both sugars until well combined.

Whisk in the egg and vanilla until fully incorporated.

Fold in the flour, baking soda, baking powder, and salt until a few flour streaks remain.

Add the crushed Cadbury eggs and chopped chocolate, folding gently until no flour streaks are visible.

Cover the bowl tightly with plastic wrap and refrigerate for 30 minutes.

Preheat the oven to 350°F (175°C) and line a cookie sheet with parchment paper.

Scoop out heaping 3 tbsp. portions of dough and place them on the cookie sheet with at least 2 inches apart.

Top each cookie with additional crushed Cadbury eggs if desired, and bake for 10-12 minutes until the edges start to turn golden brown.

After removing from the oven, use a larger cup or bowl to gently press the cookies into a round shape.

Press a chocolate bunny into each cookie while they are still warm, about 5 minutes out of the oven.