**Line the Pan:** Line an 8x8-inch baking pan with parchment paper, leaving some overhang for easy removal.

**Mix Dry Ingredients:** In a large mixing bowl, combine the oats, chopped nuts, dried fruit, and chocolate chips if using. Set aside.

**Heat Wet Ingredients:** In a small saucepan over low heat, combine the peanut butter, honey (or maple syrup), and brown sugar. Stir until the mixture is smooth and the sugar has dissolved. Remove from heat and stir in the vanilla extract.

**Combine:** Pour the peanut butter mixture over the dry ingredients. Use a spatula to mix thoroughly until all the oats are coated.

**Press Into Pan:** Transfer the mixture to the prepared baking pan. Press it down firmly and evenly with the back of a spatula or your hands.

**Chill:** Refrigerate for at least 1 hour, or until the bars are firm.

**Slice:** Once chilled, lift the bars out of the pan using the parchment paper and cut them into squares or rectangles.