Well, all of mine were weaned in the baby rice & pureed pear era, so I don't know anything about BLW.
But I am queen of menu planning. I plan for 4 weeks at a time and get a massive Sainsbury's delivery on the first day, then top up perishable stuff like fruit, milk etc. on a weekly basis.
I have two fridges and two freezers (family of 5) and am worryingly obsessive about which ones are used for what types of food, e.g. all meat goes in outside freezer, while day to day things like frozen peas or potato wedges are in the kitchen freezer.
I do the plan by putting in the things I definitely know, e.g. Thursday is DD's ballet day, so it's always a really quick pasta meal or similar on Thursdays. I also usually plan a roast for Sunday and then leftover roast chicken & chips for Monday or Tuesday.
Then I try and fill in the blanks, but we tend to have the same meals twice each month. For instance, if you're making the base of a cottage pie, it's as easy to make two as one. Likewise with things like fishcakes, or pasta sauce, or homemade chicken nuggets, which are probably quite good for babies going onto finger food.
Also, because I do the 'top-up' shop on a Monday, I try to plan meals that use very perishable things (e.g. salad leaves) for early in the week so I don't get to my planned meal for Friday and find a miserable little bag of soggy lettuce.
That's it really. Doesn't always work 100% but I definitely find the meal preparation easier and spend a bit less... or at least, I have a much better grasp of how much I'm spending.
HTH!