Preheat the oven to 350 degrees Fahrenheit and line a large baking sheet with parchment paper. As an alternative, you can spray the cookie sheet with cooking spray.

Add the eggs, peanut butter, and pure maple syrup to a large bowl and mix well until everything is combined. This substance should be thick and sticky. Note: you can use an electric mixer or a stand mixer fitted with the paddle attachment if you prefer it over hand mixing. If you do so, beat on medium speed and scrape the sides of the bowl as needed.

Transfer the oats, cinnamon, sea salt, raisins, and nuts (if adding) to the large mixing bowl and mix the dry ingredients into the wet ingredients until a thick dough forms.

Use a spoon, cookie scoop, or small ice cream scoop to drop mounds of cookie dough onto the prepared baking sheet. Note that the cookies will remain in the same form throughout the baking process, so if you want flatter cookies, you will need to flatten the dough into disc shapes. I don't mind thicker cookies, so I leave the balls of cookie dough fairly large and I don't flatten them out.

Bake on the center rack of the preheated oven for 7 to 10 minutes, or until the edges are golden brown.

Allow the cookies to cool for at least 15 minutes before moving them. If you try moving or eating the cookies while they are still warm, they will fall apart relatively easily. If you'd like, you can move them to a wire rack after cooling.