Preheat your oven to 350 degrees.
Mix together flour, sugar, Nesquik, and salt. Stir the baking soda into the milk. Mix the eggs, baking soda/milk mixture, and the vanilla extract into the flour/Nesquik mixture.
Grease & flour a 9x13 baking pan or casserole dish (or spray with Bakers Joy). Pour in the cake batter & cook at 350 for 30 minutes.
A few minutes before the cake is to come out of the oven, mix together the topping ingredients with a whisk. Pour over the hot cake once it comes out of the oven. Allow to cool.