In a medium bowl, sift together 1 1/2 cups flour, the granulated sugar, baking powder, and salt; set aside.

In a second bowl, whisk together the egg, milk, canola oil, and vanilla.

Using a rubber spatula, fold dry ingredients into egg mixture.

Spray each mason jar with cooking oil.

Pour batter into each jar only filling half way.

In a medium bowl, combine remaining 2 1/2 cups flour, brown sugar, and cinnamon.

Pour melted butter over flour mixture, and toss with a rubber spatula until large crumbs form.

Top each jar with crumb topping.

Place all jars on a cookie sheet.

Bake in a preheated oven at 325 for about 20-30 minutes or until knife comes out clean.

Allow to cool the jars will be very hot.

The cakes stay fresh with the lid for up to 1 week. You can also freeze them.