would another solution to the "dessert " question be to eat the cake together with some bread? and if so , would putting a few "crumbs" of bread on top of the piece of cake and then putting the cake - sprinkled - with -bread crumbs into one’s mouth suffice ?

ב"ה Shalom The Shulchan Aruch (שולחן ערוך קעז ,ג) mentions this solution when one is having fruit in the middle of a meal, but as part of the main meal. Since there is a difference of opinions in regard to the saying the bracha on fruit in such a case, he suggests eating the fruit with bread. In other words, if someone eats avocado which is a fruit on bread as part of his meal and then decides to have a piece of avocado on its own without bread, he would not have to make a brecha on the avocado he eats without the bread. However, this does not apply to cake since the intention of the cake is a dessert and not a main part of the meal. (See (כף החיים וערוך השולחן, סי' קעז So, what is advised in regard to cake for dessert, is to eat it after birkat Hamazon or to have in mind that your bracha of Hamotzi is not intended for the cake you're going to eat for dessert and then will make mezonot on the cake in the middle of the meal. All the best