Preheat oven to 350 degrees. Line two baking sheets with parchment paper or silpats.
Cream butter, peanut butter and sugars together in mixer (about 3 minutes).
In a large bowl, toss oats, cinnamon and baking soda together.
Add eggs to butter & sugar mixture one at a time. Make sure the eggs are mixed in well. Add vanilla and salt. Mix to combine.
Add the oat mixture to the bowl and then slowly add the "stuff" and mix until it is incorporated. No need to worry about over-mixing because there is no flour.
Using a small ice cream scoop or spoon, scoop the cookie dough onto the lined baking sheets. Space them about two inches apart. Flatten the tops a bit with the bottom of a glass. Sprinkle with fleur de sel if you wish.
Bake for 10 minutes - turning halfway through the baking time. Cool on a rack but sneak at least one while they are warm.