Prepare cracker crust. Preheat oven to 350°F. Butter muffin tin and set aside.

In large bowl, combine crushed crackers, 1 cup shredded cheddar and melted butter, mixing well until mixture sticks together and resembles wet sand. Fill muffin cups with mixture, and using your fingers, press crust firmly into bottoms and halfway up sides of each muffin cup.

Cook pasta in large pot of salted, boiling water. Cook pasta for about 6 minutes (or until al dente), rinse and pour into large bowl. Add Boursin cheese, remaining 1 cup shredded cheddar and butter. Mix well until thoroughly coated.

Whisk eggs, milk, sour cream and salt in another bowl. Pour egg mixture over macaroni; toss to coat. Fold in reserved bacon and chives. Fill each muffin cup with 2-3 tablespoons of macaroni mixture. Sprinkle each with remaining cheddar and additional chives. Bake for 20-25 minutes or until lightly golden and thermometer reads 160°F. Let cool for at least 10 minutes. Gently loosen edges of muffins with a butter knife to remove from pan.