Toast the oats and any nuts. Either toast them in a hot skillet or on a backing sheet in the oven at 350 for about 6-8 minutes. Put in a large bowl when finished.
Add honey, butter, and brown sugar to a small saucepan. Cook over medium heat until the mixture starts to bubble. Then cook an additional 1 minute. Remove from heat. Wait 2 minutes.
Stir the vanilla and salt into the mixture in the pan. If you are using peanut butter as a mixin, stir it in as well.
Pour the mixture in the pan over the oats and nuts and stir with a large spoon or silicone spatula. Add the rest of the mixins (except chocolate) to the bowl and stir to incorporate evenly.
If you are using chocolate as a mix in, wait about 10-15 minutes for the rest of the ingredients to cool and then mix in
Line a baking sheet with parchment paper or a silicone liner. If using parchment paper, spray with non-stick cooking spray.
Transfer the mixture to the baking sheet and use a greased measuring cup or silicone spatula to press the mixture into a rectangle about ¼ to ½ inch thick.
Refrigerate for about 2 hours to set. Then cut into bars. These can be stored in the refrigerator in an airtight container - separate any layers with wax paper.