I think the secret (if you love mint) is the make a mint infused simple syrup ala Jason Pyle of sourmashmanifesto.com. Make a 2:1 or 1:1 simple syrup, then throw in some ice to cool it off, then throw in 7-10 mint leaves and let it steep in the fridge for 24 hours. It will make a fantastic Mint Julep. My wife likes them made with Makers Mark the best. I prefer OGD 114.
It's not as good as a freshly made Julep, but I've had varying degrees of success following this recipe:
I've tried it with Makers Mark, Buffalo Trace and Nelson County (Heaven Hill product) and all have worked well. My personal preference is for a sweeter Julep, so I usually add the entire cup of 1:1 sugar syrup to a 700ml bottle. It generally keeps in the freezer for up to 3 months, and means I can enjoy a Julep any time with a minimum of fuss. It's also great to take to parties as all you need is ice and a cup and you're away.
I don't usually like Mint hence never really enjoyed a Mint Julep. However, I have since last weekend found a good way to balance the Mint flavor to being enjoyable for me with a local honey product. The honey with the mint has really worked well for my palate. I originally thought it was the Woodford Reserve I used on the first try, I have since tried it with standard BT and FRSmB and they are all enjoyable!
So, this is what I did:
1. Dissolved a teaspoon (tried different amounts and they're all good) of local honey with an ounce of filtered drinking water.
2. Poured half an ounce of his honey syrup into a regular Old Fashioned glass/tumbler (I don't have a mint julep cup).
3. Plucked about 5-6 decent sized mint leaves and muddled them in the honey syrup in glass.
4. Filled glass with crushed ice.
5. Filled the glass until almost full with WR, BT, or FRSmB.
6. Topped off with the remainder of the honey syrup that was left over.