Preheat oven to 350 degrees F. Line a large cookie sheet with parchment paper or a silicone mat and set aside.
Beat together the butter, peanut butter, brown sugar, sugar, and vanilla in a stand mixer fitted with a paddle attachment on medium speed until smooth. (You can also do this in a large mixing bowl with a hand mixer.)
Turn the mixer speed to low and add the eggs one at a time, scraping down the sides as needed.
In a medium bowl, stir together the oats, flour, and baking soda and mix. Add the dry ingredients to the wet ingredients in 2 additions, mixing until just combined after each addition.
Use a rubber spatula or wooden spoon to mix in the M&Ms, chocolate chips, toffee bits, and coconut.
Use a medium cookie scoop to portion out the dough (about 1.5 TBSP). Roll the dough between the palms of your hands to make dough balls. Place balls on the prepared cookie sheet at least 2 inches apart.
Bake for 11 to 13 minutes until cookies start to brown. They will seem a little underdone at first, but that's okay. Let them rest for 2 to 3 minutes on the baking sheet before moving them to a wire rack to cool completely.
Notes
Old-fashioned oats can be used in place of 1-minute oats, but the cookies will be a little heartier.
The dough can be covered and chilled for up to 4 days. I recommend portioning the dough into balls before chilling otherwise it can be hard to scoop.
These cookies are about 3 to 4 inches in size after baking and while they aren’t super thick they are still quite chewy.