I've been trying for years to come up with the perfect margarita- slushy, limey, not too sweet- but always failed. The ice would turn into chips, or disappear completely, leaving me with a watery, not slushy, drink. I had issues with lime juice too; the bottled stuff tasted like crap but squeezing fresh juice took a dozen limes and a lot of time.
So I switched my goal from the classic plain lime margarita to a fruity one, and now I've been successful. I use frozen fruit, which really helps to increase the slushy consistency, and I crush my ice in the blender before I add the rest of the ingredients. And since the drink's focus is now fruit (strawberry, in this case) I only need the juice of two limes, so I'm not standing there trying to squeeze out paltry amounts of juice from a million limes.
Strawberry Margaritas, adapted from Cooking Light
3 1/2 cups frozen strawberries (you can swap in other fruits too, like peach or mango)
2 1/2 cups crushed ice
3/4 cup tequila
1/2 cup fresh squeezed lime juice (about 2 limes)
1/4 cup sugar
3 tbsp Triple Sec
1/4 tsp salt (let's be honest, there isn't a chance I measured this. I shook my salt shaker a couple times into the blender)
Lime wedge for garnish
Fill your blender with ice, and crush. Remove to a separate bowl, and measure out 2 1/2 cups.
Combine all other ingredients, through salt, and process until smooth. Pour into a large pitcher, and garnish individual glasses with lime wedge.
Makes only four margaritas, so go ahead and double it.
Make Ahead: You can make this up to 45 minutes before guests arrive and keep the pitcher of margs in the fridge. Any longer than that and your slushy consistency might start to melt away.