You are pretty much exactly right :o)
Steak is not just high in fat, but it's also very high in protein. Both protein and fat slow down digestion (as well as foods with fiber) because they are more complex molecules that take longer for the body to fully breakdown. So, what's happening is that your humalog is working on the other carbohydrates in your meal (while 50% of the protein is converted to glucose and 10% of the fat is converted to glucose as well). But, because the digestion is slowed down so much, the effects of the humalog wear off before all your dinner has finished digesting. Therefore, your blood sugars continue to rise for an extended period of time (more so than normal). Your BGs may not peak for 4-6-8-10 hours later, depending on how much fat, protein, and fiber are in the meal.
For those wearing an insulin pump, they can do something called a "combo bolus", where a chunk of insulin is delivered immediately at the beginning of the meal, while the rest is spread out slowly over a period of time. You can do something similar to this with shots, if you don't mind injecting multiple times for the same meal. For example, say you were going to take 10 units of insulin to cover your steak meal. You decide to take 60% of the insulin immediately at the beginning of the meal (6 units). Then decide to take the other 40% (4 units) 2 hours later. (You can choose to split up your insulin however you choose - it takes some guessing & checking to eventually get the right mix that will work for you and that particular meal.) What this does is kind of stacks your insulin so when the first dose is beginning to taper off, the 2nd dose is beginning to kick in.
Because you mentioned you usually eat steak for your dinner meal, you will want to be very careful with your insulin dosages as you are sleeping. You may want to set an alarm(s) so you are able to check your blood sugars for lows. The experimenting can be frustrating at first just because you aren't sure how to properly distribute the insulin, but after a few tries you will figure it out. Most importantly: be careful of lows!
Sorry for such a long explanation! There are tons of people on here to fiddle with the "combo bolus." You can use the search function to find the different threads or ask questions on the main forum page to get lots of responses. Not everyone uses the groups tab. Good luck! Let us know if you need anything else :D