Preheat the oven to 350°. Light coat the Wilton Ice Cream Sandwich pan with Wilton non-stick baking spray.

Melt the 2 sticks of butter in a nonstick saucepan over medium-low heat; do not boil. Remove from the heat and let cool slightly. Add the sugar, eggs, and vanilla to the saucepan and stir with a wooden spoon until combined.

Add the cocoa, flour, cinnamon, chili powder, salt and baking powder and mix until smooth. Gently spread 2 tablespoon into each ice cream sandwich cavity. Bake 15- 20 minutes. Cool in the pan.

Slightly soften ice cream in microwave. Spread ice cream evenly over half the brownies and place second brownie half, top side up, atop ice cream, pressing slightly to adhere. Wrap in plastic wrap and freeze until firm, at least 4 hours.

Prepare the candy melts as instructed on the package. Working with 1 ice cream sandwich at a time, sandwich in melted chocolate, allowing excess chocolate to drip back into bowl, sprinkle on walnuts and press them gently into chocolate. Place on a baking sheet and continue. Return to sheet in freezer. Freeze until chocolate sets and freezes, about 1 hour.