Step 1: Preheat your oven to 350°F (175°C). Line an 8×8 or 9×9 inch baking pan with parchment paper, leaving an overhang on two sides.
Step 2: In a large mixing bowl, combine the melted butter, light brown sugar, and dark brown sugar. Whisk vigorously until smooth and well combined.
Step 3: Add the eggs one at a time, whisking well after each addition until fully incorporated and the mixture is glossy.
Step 4: Stir in the vanilla extract and the finely minced or mashed black garlic until evenly distributed.
Step 5: In a separate small bowl, whisk together the all-purpose flour, baking powder, and salt.
Step 6: Gradually add the dry ingredients to the wet ingredients, mixing on low speed or by hand until just combined. Be careful not to overmix.
Step 7: Gently fold in the toffee bits and chopped pecans (if using) until evenly distributed throughout the batter.
Step 8: Pour the batter into the prepared baking pan and spread it evenly with a spatula. If desired, sprinkle a few extra toffee bits or flaky sea salt on top.
Step 9: Bake for 25-30 minutes, or until the edges are golden brown and a toothpick inserted into the center comes out with moist crumbs, but not wet batter. The center should still look slightly gooey.
Step 10: Allow the blondies to cool completely in the pan on a wire rack before lifting them out using the parchment paper overhang. Once cooled, slice into squares and serve. Store in an airtight container at room temperature.