Blessing 'Hamotzi' on a Small Piece of Bread for Eating Pizza

I made pizza and want to eat 2 slices. The pizza dough is made only with milk and cream, without any water. Since it's doubtful for establishing a meal, I want to take a small piece of bread, wash my hands, and bless it with 'Hamotzi'. Will this be effective?

First of all, one does not wash hands for a piece less than a k'beitza, and moreover, this will not resolve the doubt regarding the blessing on the pizza, since bread does not exempt other foods unless one eats enough to be satiated, not just a little to exempt. Since you are eating only a small amount of bread, you will have a doubt whether you need to bless 'Mezonot' again.

The source of the words that eating a little bread does not help is written by the Magen Avraham in Siman 177, SK 1: "Therefore, it seems to me that if one does not wish to eat bread and eats a little bread and blesses 'Hamotzi' on it, it does not exempt the foods, for we do not hold like R"CH who says bread exempts all kinds of foods, but only if one establishes his meal on the bread do we say that all foods come because of the bread, but if one does not wish to eat bread, it does not exempt, and certainly if one eats less than a k'zayit, as it seems to me," and this was copied by the Mishnah Berurah there. And the Machatzit HaShekel wrote in Siman 168, SK 25: "And I have already written above [SK 18] that what one eats bread first means only in the manner of establishing, but eating a little bread does not exempt other foods. And so wrote the MA at the beginning of Siman 177. And so is the law everywhere mentioned in this Siman that one eats bread first, means in the manner of establishing:"