You go for the ribbon first and then follow this by heading to the kitchen.

Once the dog is released from the box, this triggers the first phase of RNG of missing letters scattered across rooms. You want them to be ideal for your intended route.

The second phase of RNG will be a random object (of three) missing from the kitchen cabinet. The object you want to be missing is the mixing cup, as it can be found in the bathroom along your standard route.

The missing objects are always found in the same place, and the least desirable is the mixing bowl which appears in the garden and adds an extra step of cleaning the dog afterwards.

Don't grab the chocolate chips before the dog is handled as he will take them!

The slowest part of the run is the mixing of the cake.

You want to blow the balloons and add the letters last.

Once the last letter is placed, the timer ends.

I believe if you use the right save file you will only have to worry about the ordering of the letters, as you will always have the milk jug missing. I also believe the optimal letter route is this: fridge, bathroom, laundry.

Another thing, you have to place your cursor (while invisible) to the next ingredient ahead of time as the animation plays if you want to have an optimal speed when mixing the cake.