Preheat your oven to 180°C (350°F) and line a muffin tin with paper liners or lightly grease it.
In a large mixing bowl, whisk together the flour, sugar, baking powder, and a pinch of salt until evenly combined. This creates a dry, slightly grainy mixture with a fragrant aroma.
In a separate bowl, vigorously mix the peanut butter, eggs, milk, and melted butter until smooth and slightly frothy. The mixture should feel creamy and smell nutty.
Pour the wet mixture into the bowl with the dry ingredients and gently fold together with a spoon or spatula. Do not overmix; just combine until there are no visible dry spots. The batter will be thick but moist.
Using a spoon or scoop, evenly distribute the batter into each muffin cup, filling about two-thirds full. The batter should mound slightly above the rim of each cup.
Bake in the preheated oven for 20-25 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out clean. You’ll hear a gentle sizzle as the muffins rise and bake.
Remove the muffins from the oven and let them rest in the tin for about 10 minutes. This helps them set and makes removal easier.
Gently transfer the muffins to a wire rack and allow them to cool slightly. They’re best enjoyed warm or at room temperature, with their fragrant aroma inviting you to take a bite.