As someone who tends to end up as the cared for rather than the carer, I just wanna unironically thank all the Lisa-like carers in the world who do this nice shit for others. Cooking and shopping actually take up so much more time/require more skill than is readily appreciable.
If she doesn't like green peppers, just don't use green peppers. Seriously, just use a healthy vegetable she likes instead. This is like covering broccoli in cheese: you ate the healthy food by making it unhealthy.
Unless someone is so picky it's a real problem, just accept their preferences. I've never understood the idea of forcing/tricking someone into eating a food they don't like. Picky babies who won't even try something, sure, okay, here comes the airplane. Teens or adults? No.