Pineapple Ginger Mojitos with Spiced Rum

pineapple juice

Large thumb-sized piece of ginger (slices (no need to peel))

small bunch mint leaves

Juice of half a lime

lime sliced

crushed ice

spiced rum (I use Captain Morgan Original Spiced Gold Rum)

club soda

unsalted butter

slices fresh or tinned pineapple

light brown soft sugar

Mint sprigs