Preheat oven to 350.
Cover large sheet pan with cooking spray, aluminum foil, or silicon mat.
Layer saltine crackers on to baking sheet.
Add butter and brown sugar to a saucepan and begin to boil on medium heat.
Once mixture begins to boil, stir continuously for 3 minutes (or 280 degrees using a digital thermometer).
Pour mixture on to crackers and spread to coat each cracker completely.
Place into oven and bake for 5-8 minutes or until toffee begins to harden.
While crackers are baking, heat almond bark according to package instructions until melted.
Remove crackers from oven, spread melted almond bark evenly onto crackers. Keep on counter to cool.
When crackers are at room temperature, break them apart in fridge to further cool.
Store in an airtight container in the fridge up to 1 week.