First of all frozen food is fine, but if you precook meals for 3-4 days there is no need to freeze them, they will be fine in the fridge.
1.Make more than is needed for one portion
When preparing baby food, one portion is tiny. Make at least 4 or even more. It takes exactly the same time.
2. Storage boxes
Use you favorite internet shopping service. On Amazon, you can buy useful small plastic boxes for mashed food. Buy in advance and you will use them when the child moves from milk to real food. There are trays of small containers, which are great to put into the freezer.
3. Prepare food per tray and you can mix them later
Separate the carrots, potatoes, apple, pear or mashed cooked chicken and freeze them in these containers which hold 50-80 ml. When you take them out, you let them warm up on room temperature (preferably) or in microwave. If you don't have enough time, instead of the microwave, you can use a hot bath on the stove. You choose the ones you want and mix them. This allows you to have an apple-carrot-chicken meal for example.
4. Use handy tools like steamer-blender
This is an outstanding tool that does not cost more than 30 USD. You clean the ingredients and you put them into it. It will steam first and then mash the steamed food. Cool!
5. Always plan in advance
Plan the meals and dishes 1 to 2 weeks ahead and write them down or put them into your meal planner. If you have some free time on the week-end, clean some vegetables, cook them, mash them and put them into the fridge or freezer. You will be happy to use these when you are busy.