Wash the vegetables thoroughly with water, remove the peel from the zucchini, peel the onion.
Cut the peeled zucchini into medium-sized cubes, place in a saucepan, cover with water and simmer until soft. Meanwhile, chop the peeled onion and fry in a hot frying pan with oil until lightly browned.
When the zucchini is ready, drain the water, add the fried onion and use an immersion blender to puree the mixture. Add salt, sugar, tomato paste, vegetable oil, mayonnaise, vinegar and hot red pepper to the vegetable pulp. Mix all ingredients thoroughly and continue to simmer the caviar over low heat for 2 hours, stirring the dish occasionally. Place the finished caviar in sterilized jars and roll up.
Quickly serve tender squash caviar warm or cold as an independent snack dish, garnished with parsley or dill.