Bring a kettle full of water to a boil. You will need 1 ¼ cups of boiling water to soak the oats.

In a small bowl, toss chocolate chips with rum. Each chip should be coated and glistening. Sprinkle the chocolate chips with 2 tablespoons flour and toss until coated. This will keep the chocolate chips from sinking to the bottom during baking. Set aside.

Add rolled outs and cubed butter to a large bowl. Measure out 1 ¼ cups of boiling water and pour over oats and butter. Gentle stir to moisten the oats and melt the butter. Set aside for 25 minutes.

While the oats are soaking, preheat your oven to 375°F and place a rack in the center of the oven. Butter a 9 by 13 baking dish and set aside.

In a separate bowl, whisk together eggs, granulated sugar, dark brown sugar, salt, baking soda, baking powder and cinnamon until combined. Add the oatmeal butter mixture and stir until well combined. Add the remaining flour and gently fold in. Be careful not to overmix here. Once the flour is completely incorporated, fold in the chocolate chips. Carefully pour the batter into the prepared baking dish.

Bake for 35 - 40 minutes or until a toothpick inserted in the center of the cake comes out clean.

Let the cake cool in the pan for at least 30 minutes.

While the cake is cooling, prepare the cream cheese frosting. In the bowl of a stand mixer fitted with a paddle attachment, mix butter on medium speed until smooth. Add the softened cream cheese and mix on medium until combined.

Add the confectioners' sugar and vanilla extract and mix for a few seconds on low. Increase the speed to medium and beat until smooth (about 1 to 2 minutes). Transfer the frosting to a smaller bowl, cover and refrigerator for at least 20 minutes.

To assemble the cake, simply spread the frosting over the cooled cake in an even layer. You can chill the cake for 15 minutes to let the frosting set; however, I couldn't wait that long and sliced a piece immediately.