Since I assume this question is less about Eichmann's favorite breakfast food and more about what his job entailed, I'm going to answer with regards to the latter. Especially since we don't have Eichmann's official diary as we do in the case of Himmler, so reconstructing what he did on this or that day is only re-countable through indirect sources or the stuff others have written down.

Anyways, Adolf Eichmann was important because he and his office, the Referat IV b 4 of the Reich Security Main Office, was responsible for a variety of anti-Jewish measures but most importantly for coordinating deportations and coordinating with Jewish councils about who was going to be deported to the camps and for coordinating deportations with foreign governments resp. "advising" them in the "Jewish question".

So basically, when a deportation to a ghetto or camp in Eastern Europe was planned, it feel to the Eichmann office to contact the Reichsbahn, the national German railway, to order to appropriate amount of train space and coordinate payment for it. Usually six weeks in advance, the Eichmann office would contact Section 21 "special travel trains" of the Reichsbahn department for mass transportation and order the needed amount of train cars plus personnel. Deportation trains did pay a special price with the Reichsbahn of about 2 Pfenning per kilometer as per the group concession on Reichsbahn tickets. The Eichmann office would then either take the money needed for the deportation off of the people slated to be deported or force the Jewish community from which they were deported to pay for it.

Also, the Eichmann office frequently contacted Jewish councils in order to draw up the lists of who was to be deported. Similar to the concept of the Kapo in Concentration Camps, the Nazis worked hard to basically make their own victims to appear complicit in their own murder. In case of the head of the Warsaw Ghetto, Adam Czerniaków, this lead to his suicide after a meeting with Eichmann.

Eichmann was also the person one called if you wanted Jews to be deported. In the case of Serbia, when the national uprising broke out in the summer, autumn 1941, the Wehrmacht commander in charged wanted to deport the male Jews of Serbia because they saw them as responsible for the uprising so they first contacted the German Foreign Office, which in turn called Eichmann. The responsible bureaucrat from the Foreign Office wrote down in the margins of a document concerning the Serbian Jews "Eichmann suggests shooting them". Because at that point in time deportations of non-German Jews had been halted, so Eichmann was under orders from his boss Heydrich that no Jews from outside the Reich could be deported.

Similarly, Eichmann's office also send "Consultants on the Jewish Question" into several occupied and allied territories in order to organize deportations from there. Dieter Wisliceny in Saloniki, the Brunners in Slovakia, and Eichmann himself in Hungary in 1944, they all were the local organizers of drawing up lists and organizing trains and their payment.

This is basically, what Eichmann did all day. The organization of deportations of people to their deaths. To this end he would have phoned, corresponded, and read reports all day long while thinking of the most efficient ways to get people into the camps to be murdered.

Sources:

• Raul Hilberg: The destruction of the European Jews.

• Raul Hilberg: Sonderzug nach Auschwitz.

• Hans Safrian: Eichmann's Men.

• Hans Günther Adler: Der verwaltete Mensch: Studien zur Deportation der Juden aus Deutschland.