Begin by soaking the pitted Medjool dates in warm water for about 10 minutes. This softens them and makes them easier to blend.
In a food processor, combine the soaked dates, peanut butter (or nut butter), vanilla, and maple syrup. Blend until the mixture is smooth and creamy.
In a large mixing bowl, combine the quick oats, chopped nuts (or seeds), dried fruit, cinnamon (if using), and sea salt.
Pour the date and nut butter mixture into the bowl with the dry ingredients. Stir until everything is well combined. You may need to use your hands to ensure everything is evenly mixed.
Line your baking dish with parchment paper. Transfer the mixture to the dish, pressing it down firmly to create an even layer.
Place the baking dish in the refrigerator for at least 1-2 hours to allow the bars to set. This helps them hold their shape when cut.
Once set, lift the bars out of the baking dish using the parchment paper. Cut into squares or rectangles, and enjoy your homemade Trail Mix Bars!