I had the same issue, so I tried removing mods and CC but that didn't fix it. Apparently, the game was labelling flour, sugar and other ingredients as debug. Repairing my game did the trick 🙂
Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 1.101.290.1030
What expansions, game packs, and stuff packs do you have installed? All except the Home Chef Hustle stuff pack and Batuu game pack.
Steps: How can we find the bug ourselves? With Simple Living lot challenge on, and the required ingredients in the fridge, click on cook, then sweets, then find any cupcakes and try to click on them.
What happens when the bug occurs? The cupcake option is not clickable and neither flour nor sugar is counted in the required ingredients list even though both are in the fridge or Sims inventory. In the save I tried this in, I have double the amount needed. The ingredients are counted for other cookies or recipes, but none of the cupcakes. Milk or eggs are counted, but not flour nor sugar.
What do you expect to see? That I will be able to cook cupcakes by clicking the stove or the fridge with the Simple Living Lot challenge activated and required ingredients in the fridge or sims inventory.
Have you installed any customization with the game, e.g. Custom Content or Mods? Not now. I've removed them.
Did this issue appear after a specific patch or change you made to your system? Yes
Please describe the patch or change you made. The latest patch 1.101.290.1030 that updated the cupcakes so they can be cooked with the stove.
As you can see the flour and sugar is counted in the recipes above the cupcakes in the list, but not the cupcakes. I removed ALL mods, even cc, so empty mods folder, deleted localthumbcache every time I load, AND I tried with a new save, and as soon as I use the simple living lot trait, I can't cook the cupcakes, because flour and sugar doesn't get counted for the cupcakes, even though I have flour or sugar in the fridge. Second image is from second save I tried this in:
