Line a 11x15 sheet pan with parchment paper or aluminum foil. Preheat oven to 350 degrees.
Spread crackers in a single layer on the sheet pan.
In a heavy 2 quart pot, melt butter. Add sugar and corn syrup. Bring to a boil over medium-high heat. Stir constantly until mixture boils. Boil 2 mintues, time precisely.
After 2 minutes, remove from heat and add baking soda. Stir until combined.
Pour caramel mixture evenly over crackers. Bake at 350 degrees for 10 minutes. Quickly remove crackers from sheet pan to wax or parchment paper using a spatula. Allow to cool completely.
When cool, melt chocolate and spread over crackers. Allow to cool.
Make ice cream
In a medium mixing bowl, add milk, sugar, cream and vanilla. Mix with a whisk or mixer until sugar is dissolved about 2 mintues.
Turn on the machine and pour the mixture into the freezer bowl. Mix until thickened about 25 minutes.
Break Crack Candy into pieces and stir into ice cream.
Serve soft, as is, or transfer to a freezer safe container with an airtight lid. Freeze until firm about 2 hours. Remove from freezer about 15 minutes before serving.