Fill up the serving glass with ice (preferably crushed but cubed will work just fine)
Add all ingredients (except the Thai pepper) in a cocktail shaker, add ice and shake vigorously for 10-15 seconds
Strain over ice (add more ice to make a half dome)
Garnish with a Thai pepper or cilantro. (If you have a brûlée torch, roast the pepper prior to garnishing)
Combine 1/4 cup chili flakes, 1/2 cup water and 1/2 cup sugar in saucepan. Bring to a boil over high heat (until sugar dissolves, about 2 minutes). Turn the heat down and let simmer for 5 minutes. Take the syrup off the stove and let it cool completely. Fine strain through a fine sieve to discard all solids and transfer the syrup into a glass bottle or jar. When stored in the refrigerator, this syrup is good for up to 2 weeks. If you like a little spiciness in your life you can use this syrup to jazz up all of your cocktails.
As we already mentioned, you can make this cocktail with ice cubes but it is much better with crushed ice. A hand ice crusher is relatively cheap and believe me, buying one is worth the investment especially if you're planning on making cocktails with us. As you probably already know we have a huge crush on ice :)