Irish Cream Fudge

I had a little Irish Cream left after making Erin's birthday cake so I decided to make this fudge. I've never made fudge before, and I'm not sure why you have to boil the sugar for 11 minutes, not 10. But it's pretty good and you can taste the Irish Cream. Other recipes I've came across use white chocolate, but I'm not a big fan of that so I used this recipe.

Bailey's Irish Cream Fudge Recipe
1. In a very large bowl, combine:

2 pkgs milk chocolate chips, 12 oz. EACH
1 (12 oz.) pkg. semisweet chocolate chips
2 jars marshmallow cream, 7 oz. EACH
2 t. vanilla
2/3 c. Bailey's Irish Cream
2 c. chopped nuts -- optional

2. Set aside.
3. Line a 10x15" pan with foil and spread lightly with: butter

4. In a saucepan, combine:

4 1/2 c. sugar
1 (12 oz.) can evaporated milk
1/2 lb. butter

5. Bring to a boil over medium heat.
6. Cook slowly, stirring constantly for 11 minutes.
7. Pour milk mixture over the chocolate chip mixture.
8. Stir slowly by hand to blend. (Do not use a mixer.)
9. Pour into prepared pan.
10. Chill until set.

Makes about 5 pounds of fudge.