New York City stinks. Garbage, exhaust, crowds of human beings, and who really knows what. Fortunately there are little pockets of fragrance everywhere. My favorite city smell comes from the street-nut carts. The men who mind the carts stand all day long tossing peanuts in sugar over heat in copper drums, sending burnished sugar smoke wafting down the sidewalk. There’s no need to advertise or call out for customers. That smell, on an early fall afternoon, half hot and half cool, is like a magnet. This candied–peanut butter cake is an ode to those nut-cart guys. Thank you for making New York a little more wonderful. Add 2 cups of raspberries to the cake if you’d like a peanut butter and jelly effect, or keep it plain for simple butter-nut bliss.
Prepare the peanut topping: In a small saucepan, combine the butter, sugar, honey, and cream. Heat the mixture over medium heat until the butter is melted, stirring occasionally. Bring the mixture to a boil over medium heat, until a bit lighter in color, about 3 minutes. Add the peanuts and cook until the caramel thickens slightly, 1 minute more. Transfer to a bowl and let cool, stirring occasionally, while you prepare the cake batter.
Prepare the cake: Preheat the oven to 350°F. Butter a 9-inch round springform pan.
In a small bowl, whisk together the flour, baking powder, and salt. In a large bowl, beat the butter and sugar with an electric mixer on medium speed until fluffy, about 3 minutes. Beat in the egg and vanilla. On low speed, beat in half of the flour mixture, then the milk, and then the last half of the flour mixture.
Transfer the batter to the prepared pan and smooth the top. Dollop the top of the batter with the peanut mixture and spread it out evenly. Bake the cake until the top is caramelized, the cake is set, and a toothpick inserted into the center comes out with moist crumbs attached, 55 to 65 minutes. Cover the cake with foil if it starts to brown too quickly.
Transfer the pan to a wire rack and let cool for 15 minutes, then remove the ring and let the cake cool completely before serving.