Preheat your oven to 180°C (350°F) and line your muffin tin with paper liners or lightly grease it.
In a large mixing bowl, whisk together the flour, baking powder, and salt until evenly combined. This creates a light, airy base for your muffins.
In a separate bowl, combine the creamy peanut butter, brown sugar, and eggs. Use a spatula or whisk to blend until the mixture is smooth, slightly fluffy, and fragrant with roasted peanut aroma.
Gradually add the milk to the peanut butter mixture, stirring constantly. The batter should become thick but stirrable—if it feels too stiff, add a splash more milk until it reaches a smooth, scoopable consistency.
Gently fold in the chocolate chips or chopped nuts, if using. Be careful not to overmix, to keep the muffins tender and light.
Spoon the batter into the prepared muffin cups, filling each about three-quarters full. Use the back of a spoon to smooth the tops if needed.
Bake for 18-20 minutes, or until the muffins are golden on top and a toothpick inserted into the center comes out clean. The kitchen will fill with a warm, nutty aroma as they bake.
Remove the muffins from the oven and let them sit in the tin for about 5 minutes. Then transfer them to a wire rack or plate and let cool slightly before serving.
Enjoy these warm or at room temperature. They’re perfect with a glass of milk or a steaming cup of coffee for a cozy morning treat.
