Homemade Creme de Menthe Syrup: Muddle 1 cup of Mint leaves and set aside. Combine 1/2 cup of water and 1/2 cup of granulated sugar in a saucepan and bring to a simmer. Add muddled mint leaves. Simmer together for 10 minutes. Remove from heat and allow to cool slightly. Strain out mint leaves if desired. This homemade syrup recipe will yield more than the amount required in the Mint Julep recipe. So you can make extra Mint Juleps, or save it for later.