Start by lining a baking dish with parchment paper, and set aside.
Add the peanut butter, pure maple syrup, and vanilla extract to a stock pot over low heat, and stir until the mixture is well combined. This should take 1-2 minutes.
Remove from heat and stir in the rolled oats, flaxseeds, sea salt, and any optional add-ins. Mix well.
Pour the mixture into the lined baking dish and flatten to about 1-inch thick. Place in the freezer to set for 15 minutes.
Remove from the freezer and cut into squares.
Store in the fridge or freezer until ready to enjoy!