Brownies Isi Selai Kacang

Bahan-bahan (16 porsi)

• 1 cup (250g) smooth peanut butter spread for stuffing
• 1 tsp salt flakes (, divided)
• 200 g / 14 tbsp unsalted butter ((1 3/4 US sticks))
• 1 1/4 cups (200g) dark chocolate chips ((7 oz) (Note 2))
• 1 cup loosely packed brown sugar (, loosely packed )
• 3 large eggs (, lightly beaten)
• 1 tsp vanilla extract
• 1/2 cup plain flour
• 1/4 cup cocoa powder
• 1/8 tsp cooking salt / kosher salt