Step 1

Melt butter completely.

Step 2

Mix butter with oatmeal, flour, and brown sugar.

Step 3

Press 2/3 of this mixture into a greased (I also like using parchment paper) 9x13 pan and bake at 325ºF for 10 minutes. When done, allow it to cool.

Step 4

Set remaining 1/3 of crust aside for topping.

Step 5

While crust is baking, melt butter for filling in a saucepan.

Step 6

Stir in brown sugar until smooth. (about 1 minute)

Step 7

Repeat for milk, vanilla, and flour, adding each one separately.

Step 8

Bring to a slow boil for about 3 minutes until it begins to thicken. Be sure to stir continuously.

Step 9

Remove from heat.

Step 10

When crust is cool to the touch, pour caramel filling on it.

Step 11

Sprinkle remaining crust mixture over top.

Step 12

Bake at 300ºF for an additional 20 minutes.

Step 13

Bars will appear a bit runny but will firm up when cool.