One minute muffins AKA "muffins in a mug" are pretty fast and foolproof to make, and can have all sorts of bits and bobs added to them for variety. Look in our low carb recipes section, or try googling. If you are a keen cook, then there are also all sorts of other low carb cakes, biscuits, and puddings, etc that you can bake using ground almonds, coconut flour, etc. And these will actually be good for you as they are great sources of fats and fibre. You can make many of these with or without sweetening according to individual taste.
I normally include berries with yoghurt or cream as a part of one of my meals, and by just having a tiny portion can keep well within my (very) low carb diet.
Robbity