Rim the ridge of your glass with a lime wedge and dip in a mix of margarita salt + sugar [I used about 3 tablespoons salt to 2 teaspoons sugar]. Fill the glass with ice. In a cocktail shaker, combine tequila, grand marnier, simple syrup and lime juice with ice, and shake for about 30 seconds. Pour over ice and squeeze in lime slices and add a few peach chunks.
For peach simple syrup: combine equal parts sugar and water, bring to a boil and let sugar dissolve, then turn off heat and let cool completely. Combine 1 cup simply syrup + 3 peeled and chopped peaches in a blender and blend until combined. This makes enough simple syrup for 3-4+ margaritas, so I suggest playing with the amounts once you know how much syrup you like in your drinks!
This recipe can be easily doubled, quadrupled, etc. Since everyone’s tastes differ, add simple syrup 1/4 cup at a time and go from taste. I also suggest buying the lime juice if you plan on making a pitcher (or 2) considering you’d have to squeeze a billion limes to get enough juice.