How to Make It
Whisk together first 6 ingredients; cover and chill 2 hours.
Pour milk mixture into freezer container of a 1-qt. electric ice-cream maker, and freeze according to manufacturer's instructions. (Instructions and times will vary.)
Remove container with ice cream from ice-cream maker, and freeze 30 minutes.
Stir crushed cookies and liqueur into ice-cream mixture. Transfer mixture to an airtight container or a loaf pan covered tightly with aluminum foil; freeze 3 to 4 hours or until firm.
Blueberry-Lemon Zest Ice Cream: Omit cookies and liqueur. Bring 2 cups coarsely chopped blueberries, 2 Tbsp. sugar, and 2 Tbsp. water to a boil in a small saucepan over medium heat; reduce heat to low, and simmer 10 minutes, stirring often. Cool 30 minutes; cover and chill 2 to 3 hours. Meanwhile, prepare recipe as directed through Step Stir 2 tsp. lemon zest into prepared ice-cream mixture, and swirl in chilled blueberry mixture. Proceed as directed in Step Hands-on 25 min.; Total 6 hours, 45 min.
Bourbon-Butter-Salted Pecan Ice Cream: Omit cookies and liqueur; increase vanilla to 2 tsp. Prepare recipe as directed through Step Meanwhile, cook 1 cup coarsely chopped pecans and 1/2 Tbsp. butter in a small skillet over medium heat, stirring constantly, 7 to 8 minutes or until toasted and fragrant. Spread pecans on wax paper, and sprinkle with 1/4 tsp. kosher salt; cool completely. Stir pecans and 2 Tbsp. bourbon into prepared ice-cream mixture, and proceed as directed in Step Hands-on 10 min., Total 6 hours
Strawberry-Basil Ice Cream: Omit vanilla, cookies, and liqueur; reduce whole milk to 1 1/2 cups. Prepare recipe as directed through Step Meanwhile, pulse 1 (16-oz.) container fresh strawberries, coarsely chopped; 2 Tbsp. chopped fresh basil; and 2 Tbsp. fresh lemon juice in a food processor 5 or 6 times or until finely chopped. Stir strawberry mixture into chilled milk mixture. Proceed as directed in Steps 2 through Hands-on 10 min., Total 6 hours