Beat the butter with both sugars on medium speed until fluffy and pale, about 2 to 3 minutes.

Add the eggs one at a time, beating well after each, then blend in the vanilla.

Whisk together the flour, baking soda, and salt. Mix into the wet ingredients on low just until no dry streaks remain.

Fold in the chocolate chips, white chips, pretzels, toffee bits, and M&Ms with a spatula until evenly distributed.

Preheat oven to 350°F (175°C). Scoop 2-tablespoon portions onto parchment-lined sheets, spacing them 2 inches apart. Bake for 11 to 13 minutes, until the edges are set and golden and the centers look slightly underdone.

Let cookies rest on the baking sheet for 2 minutes, then transfer to a wire rack to cool completely. Sprinkle with flaky sea salt before serving.