Step 1

Preheat the oven to 350F (180C or 170C fan forced). Line baking sheets with parchment paper or silicone baking mats.

Step 2

In a large bowl beat together the butter, sugars, and peanut butter until creamy and no lumps remain.

Step 3

Mix in the egg and vanilla.

Step 4

Add in the flour, baking soda and salt. Do a few stirs by hand first, then turn the mixer to a low speed and beat together until combined.

Step 5

Turn off the mixer and stir in the quick oats and old-fashioned oats.

Step 6

Form the dough into balls about with about 1 - 1.5 tablespoons each. They'll be about the size of a ping pong ball. Place 2 inches apart on a lined cookie sheet. Do not flatten.

Step 7

Bake 1 sheet at a time for 9-12 minutes in the middle of the oven, or until the tops are just set.

Step 8

Remove from the oven. Cool cookies on the cookie tray for 5-10 minutes, then transfer to a cooling rack and continue cooling.