Begin by melting the unsalted butter in a medium saucepan over medium heat. Swirl occasionally until it turns a golden brown and has a nutty aroma. Remove from heat and let cool.
In a large mixing bowl, whisk together the flour, baking powder, and salt.
In another bowl, combine the brown sugar, eggs, and vanilla extract. Pour in the browned butter and whisk until smooth.
Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.
Using a spatula, fold in the pecans and toffee bits.
Preheat your oven to 350°F (175°C). Line the baking pan with parchment paper. Pour the batter into the pan and spread evenly. Bake for about 25-30 minutes or until golden brown.
Allow the blondies to cool in the pan for 10 minutes, then lift out with the parchment paper and let cool completely on a wire rack before slicing.
