Line an 8 x 8 pan with parchment paper or foil. Pre-heat oven to 350 degrees.
Melt the butter in a small saucepan on medium low heat until it turns a golden brown color and has a nutty smell, about 5-7 minutes. Once it starts to turn color, don't walk away as it can burn quickly. Remove from heat and cool.
Add the melted butter and brown sugar to a stand mixer or with an electric mixer until combined. Add the eggs and vanilla and mix well.
Combine the flour, salt and baking powder in a small bowl and whisk together. Add the dry ingredients to the wet ingredients and mix on low until just combined. Mix in the peaches on low speed.
Pour the mixture into the prepared pan and smooth the top. Bake for about 35-40 minutes until the edges are golden and the middle feels set. Cool completely before cutting.
Keyword blondies, brown butter blondies, peach blondies