Preheat oven to 375 degrees.

Line a cookie sheet with parchment paper.

Place a saucepan over medium-low heat and melt two sticks of room-temperature unsalted butter. Continue to stir the butter until foamy and browned, about 5-8 minutes. Let the browned butter cool for 10 minutes before moving to the next step.

Add the light brown sugar, granulated sugar, pecan liqueur, and pure vanilla extract to the browned butter and stir until smooth.

Spoon the browned butter mixture into the bowl of a stand mixer, then add two large, room-temperature eggs and mix until the eggs are fully incorporated.

In a small bowl, add the all-purpose flour, baking soda, and flaky sea salt. Mix well.

Spoonful at a time, add the flour mixture to the browned butter mixture until the mixture is combined.

Fold in the white chocolate chips, semi-sweet chocolate chips, and milk chocolate toffee bits.

Using a medium ice cream scoop, add two scoops of cookie dough per cookie, 3 inches apart.

Chill the scooped cookie dough on the cookie sheet in the fridge for 30 minutes.

Place the cookie sheet on the middle rack of the preheated oven.

Bake for 5 minutes, then turn the cookie sheet and continue baking for 6 minutes or until the edges of the cookies are light brown.

Remove the cookies from the oven and allow them to rest for 5 minutes. Then transfer them to a wire rack to finish cooling. Use a spatula to remove them from the pan.