Place butter in a small saucepan over medium heat. When the stick has melted, whisk the butter over the heat until small brown bits form at the bottom and the melted butter has a nutty fragrance. Be sure to whisk constantly so that the milk solids in the butter do not burn as they are browning. Transfer the brown butter to a bowl to cool to room temperature.
Preheat oven to 375℉. Spray an 8x8 or 9x9 inch cake pan with cooking spray and then line with parchment paper, making sure to have overhang of paper on two ends.
Combine the butter and brown sugar together in a large bowl with a hand mixer on medium-high speed until creamy. Add the egg and vanilla extract, mix until combined. Add the pecan butter and mix until combined.
In a separate bowl, combine the oats, flour, baking soda, and salt by stirring with a whisk. Add the dry ingredients to the pecan butter mixture and combine on medium-low speed just until a dough forms.
Press ⅔ of the dough into the prepared pan with your hands, being sure to press it firmly into an even layer. Spread the peach jam over the top of the dough. Sprinkle the remaining dough in ½’’ crumbles over the top of the jam.
Bake for 20-25 minutes until golden brown. Remove the pan from oven and transfer the pan to a wire rack to cool for 30 minutes, then transfer the pan to the fridge to chill for 1-2 hours. This will allow for easier cutting.
Use the parchment paper overhang to carefully remove the uncut bars from the pan. Transfer to a cutting board and cut into 16 bars. Serve at room temperature or chilled. Leftover bars can be stored in the refrigerator up to 5 days.
Nutrition information was calculate using peanut butter, and will vary depending on what type of fat, nut butter, or jam are used.