Preheat oven to 350°F/180°C. Grease or line a muffin pan.
Beat the peanut butter, butter and sugar together with an electric whisk or stand mixer for a few minutes until light and fluffy.
Beat in the eggs, one at a time, beating well after each one, then beat in the vanilla and the milk.
Sift in the flour, baking powder and salt and gently combine.
Spoon the batter into the muffin cases, ¾ full. Bake for 20 minutes or until risen and an inserted toothpick comes out clean.
Allow to cool for a few minutes in the tin and then transfer to a wire rack to cool completely before frosting.
For the strawberry jelly icing
Tip: If using jam, press the strawberry jam through a fine mesh sieve to remove any large pieces, collecting the thinner jam in a small bowl. You should have 1 tablespoon of jam in the bowl to use.
Beat the butter, sugar and strawberry jelly with an electric whisk or stand mixer until smooth. Keep in the fridge until ready to frost the cupcakes. If it’s not very pink, you can beat in a few drops of red food coloring.
You can use strawberry jam or preserves instead of jelly.
If using jam or preserves, press the strawberry jam through a fine-mesh sieve to remove any large pieces, collecting the thinner jam in a small bowl. You should have 1 tablespoon of jam in the bowl to use for the frosting.
For more strawberry flavor in the frosting, add a small teaspoonful of strawberry jelly to the cooled cupcakes, then swirl the frosting on top.
The strawberry jelly may or may not produce a color that is a deep pink. You can use red food dye or food coloring to give it a stronger pink color if desired.
When filling the muffin tins, make sure they are filled ⅔ full as any more can cause the muffins to spill over when baking.
Do not overmix the muffin batter as it can decrease the air in the mixture giving the cupcakes a flat texture.