Preheat the oven to 350. Scatter 2 cups of pistachios on a baking sheet, reserving the remaining cup for later use. Toast the pistachios for 5 minutes, until fragrant and warm. Transfer the warm nuts to a large food processor and add 2 tsp oil. Process until the nuts turn into nut butter, stopping the processor occasionally to scrape down the bottom and sides. Add another spoonful of oil if necessary to help the butter become smoother and thin out. Let the pistachio butter cool to room temperature.
In a large bowl, whisk together the melted butter and both sugars. Add the eggs and yolks, and whisk until satiny smooth. Add the pistachio butter and extracts, and mix those in as well. Next, add the flour, baking powder, and salt, and stir with a spatula until all streaks of flour are gone. Finally, add the remaining 1 cup of pistachios and the chocolate chunks, and stir them into the batter.
Line a 9x13 pan with foil and spray the foil with nonstick cooking spray. Scrape the batter into the pan and smooth it into an even layer. Bake the blondies at 350 F for 30-35 minutes, until a toothpick inserted into the center comes out with just a moist crumb or two attached. Let the blondies cool completely before cutting them.
Cut the blondie slab into three columns, then cut each column into four pieces, to give you 12 rectangular blondies. Trim two corners off the bottom of each blondie, to create the chins of your Frankensteins. Place the blondies on a cookie sheet and freeze them for about 30 minutes, until they are firm.
While you wait for the blondies to chill, place the candy melts in a large microwave-safe bowl and microwave in 30-second increments, stirring after every 30 seconds to prevent overheating. When the candy coating is smooth and fluid, use a fork to dip the whole almonds in the coating, to create the Frankenstein noses. Set the candy-coating almonds on a sheet of waxed paper to dry.
Use a fork or dipping tools to dip a blondie in the candy coating. Let the excess drip off the bottom, then gently scrape the bottom against the lip of the bowl to remove any extra coating. Set the dipped blondie on a waxed paper-covered baking sheet. Working quickly, press two candy eyes and an almond nose in the center of the blondie. Add two mini Rolos to the side of the chin for the bolts. Repeat with the remaining blondies, until you have 12 Frankenstein faces.
Melt the red and brown candy coating in two separate small bowls. Transfer them to two paper cones, disposable piping bags, or even plastic sandwich bags with a small hole snipped in the corner. Give each Frankenstein a red mouth, a brown scar on his face, and brown eyebrows. Make sure the coating is completely set before proceeding—you can refrigerate them briefly to speed this process if you'd like.
Finally, it's time to give them hair! Put the chocolate sprinkles in a bowl. Use a clean paintbrush to brush corn syrup on the top and around the sides of the Frankensteins, then push them head-down into the bowl of sprinkles, so the sprinkles adhere to the corn syrup. Store Frankenstein Pistachio Blondies in an airtight container at room temperature for up to a week.