Preheat oven to 400 F.
Line a 15x10x1 commercial sheet pan with saltine crackers making each crackers touch one another.
In a saucepan,melt butter & sugar on medium heat.Continue to cook on med-high heat until butter is completely melted and mixture is well blended;stirring frequently.Add in vanilla.Bring to a boil;boil 3 minutes without stirring.Spread evenly over crackers.
Bake at 400 degrees for 5-6 minutes. The crackers will look bubbly. Remove from oven.
Melt the chocolate chips in the microwave safe bowl until they are smooth. Spread crackers with the melted chocolate chips. Cool Completely and break into pieces.
Keep leftovers refridgerated!