Preheat the oven to 180C/350F and line a 12 hole cupcake tin with liners.
Place butter, sugar, lemon and lime zest into a large bowl or the bowl of your stand mixer and beat until light and fluffy, around 2 minutes on medium-high speed.
Add in the eggs, scraping down the sides as necessary and mix on medium speed until smooth and well combined.
Add in the salt, baking powder and flour and mix on low until the mixture begins to come together, then add the milk and continue to mix on medium speed until everything is well combined, smooth and there are no lumps of flour.
Divide the batter between the cupcake liners; I use a 2tbsp cookie scoop to ensure all my cupcakes are even.
Place in the oven for 18-22 minutes, until risen, lightly golden and an inserted skewer into the centre comes out clean.
Whilst the cupcakes are baking, make the syrup; place Strawberry Pimms, sugar and water into a medium sized saucepan over a medium heat (If using plain Pimms, add the strawberry syrup too). Bring to a boil, stirring frequently and continue to cook for 5-10 minutes until the mixture has reduced and become slightly thickened. It won't be properly thick, but as you're stirring, you will feel it change and it will coat the back of a spoon.
Once the cupcakes are baked, transfer to a wire rack with kitchen towels beneath it. Use a toothpick to poke holes in the top of each cupcake and then spoon the syrup onto the top of each cupcake, 1/2 tbsp at a time. I ended up with just over 1tbsp of syrup per cupcake.
Leave to cool completely.
Once cooled, make the frosting: Place butter, sugar, Pimms and salt into a large bowl and mix on low until the mixture begins to come together. I use a hand mixer as I like the control I have, you can also use your stand mixer.
Once the mixture starts to come together, turn the speed up to medium-high and beat the frosting until light and fluffy, around 2 minutes on med-high speed.
You want the frosting to hold its shape, but not be so thick you can't pipe it. I always grab a spoonful and then turn it upside down, it should hold, but as soon as you tap the spoon on the side of the bowl fall back into the bowl.
Fill a piping bag fitted with an open star nozzle half way and pipe a swirl onto each cupcake.
Take your halved strawberries and slice in half again. Take two slices of strawberry and place on the top of the cupcake at an angle with the tips of the strawberries touching. Place a sprig of mint on each cupcake too and serve.
Strawberry Pimms Cupcakes will keep in an airtight container, in the fridge for 3 days.