Preheat oven to 375°F.

Line a 10x15-inch cookie sheet with aluminum foil, and coat with non-stick cooking spray. Place Ritz crackers in a single layer on cookie sheet, covering the entire pan.

In a large saucepan over medium heat, melt the butter.

Add brown sugar and stir, bringing to a boil.

Cook for 2-3 minutes.

Remove from heat, and immediately stir in baking soda, whisking vigorously.

Stir in 1/4 cup peanut butter, and whisk until smooth.

Pour the mixture over crackers, spreading quickly to cover all crackers. This can be tricky because the crackers want to lift and float.

Place pan in the oven for 6-8 minutes, or until the brown sugar mixture is very bubbly and puffy.

In a large microwave-safe bowl, combine chocolate chips and remaining 1/2 cup of peanut butter, microwaving on low heat at 30-second intervals until melted and smooth.

Immediately spread the chocolate-peanut butter mixture evenly onto the candy.

Place in the refrigerator for 20-30 minutes or until set and hardened. Break into pieces.