Preheat the oven to 375° F.
Slice each brownie into five strips. Place all 10 strips on a small cookie sheet and bake them in a toaster oven (or lay them in an air fryer and cook) until they are crisp, like a crouton, about 10 to 15 minutes. (If the brownies are very fresh and moist, they might need more time to become crisp and dry throughout.) Remove them from the oven and place them on a wire rack to cool. Reserve four and roughly chop the rest into crumbles.
In a small bowl, combine the corn starch, sugar, and salt. Place the mixture in a saucepan.
In another small bowl, combine the milk and half-and-half.
Place the saucepan over medium heat, and pour in the milk mixture steadily and slowly while whisking constantly. (If you pour it in all at once, the corn starch will clump.) Once everything dissolves, bring the liquid to a boil, and then reduce the heat to medium. Whisk constantly for another couple of minutes. (If you stop whisking, the bottom will stick and burn.)
Remove from the heat and add the peanut butter, butter, and almond extract. Whisk until all the ingredients are incorporated and the mixture thickens and becomes creamy, with no lumps.
Divide evenly into four Italian-style coffee glasses or tall coffee mugs. (The pudding begins to thicken immediately, so work quickly before it sets.) Cover tightly with plastic wrap, and chill in the refrigerator for at least 1 hour to overnight.
To serve, remove the glasses from the refrigerator. Sprinkle the brownie crumbles over the top of the pudding and repeat with the peanuts.
Top the glasses with a frill of whipped topping, and dust with cocoa. Garnish each one with a brownie crouton and serve immediately.
