In a mixing bowl, combine margarine, flour, oatmeal, brown sugar, vanilla, and baking soda. Mix with a fork until crumbly.
Reserve 1 cup of the mixture and set aside.
Press the remaining mixture into a greased 9x13-inch pan.
In a saucepan, combine sweetened condensed milk, chocolate chips, and 2 Tbsp margarine. Stir until chocolate is completely melted.
Spread chocolate mixture into the pan.
Sprinkle reserved crumble mixture over the top. Press it in your hands to create bigger crumbles - these are the best part!
Bake at 350°F for 25 minutes.
