Preheat the oven to 300 F/150 C. Line a jelly roll pan with parchment or aluminum foil.
Toast peanuts in a large skillet over medium heat, until fragrant, about 5 minutes. Transfer peanuts to large mixing bowl.
Add oil and oats to skillet, and toast over medium heat, mixing frequently, until fragrant. Again, about 5 minutes. Transfer to the mixing bowl, and add salt and ground flax seeds.
In the skillet, combine honey, maple syrup, and brown sugar. Cook over low heat until sugar is completely dissolved. Remove from heat and stir in peanut butter and vanilla.
Stir wet ingredients into the dry, and mix until well combined. Add chocolate chips, if desired. Press firmly into prepared jelly roll pan.
Bake at 300 F/150 C for 25 minutes, turning the pan about halfway through. After 25 minutes, turn the oven off, but leave the pan in the oven for about 15-20 more minutes. Remove from oven, let the bars cool for about 10 minutes, then cut into 48 bars. Let cool completely. Store in an airtight container.
Notes
Adapted from America's Test Kitchen Healthy Family Cookbook.*Use gluten free oats for a truly GF snack.**Substitute other liquid sweeteners to make this treat vegan.