R. Saul Mashbaum cites a nice vort, writing:

<a very interesting pshat in "kol haochel matza erev Pesach keilu 
bo`eil arusaso beveis chamiv" is that the latter does the action 
before nissuin, which are accompanied by sheva brachot. The matza 
leil haseder is eaten after saying sheva brachot: 1) hagafen 2) 
mkadesh Yisrael vhazmanim 3) shehechyanu 4) haadama 5) asher gaalanu 
6) hamotzi 7) al achilat matza. Thus one who eats matza before the 
seder is skipping sheva brachot, as is bo`eil arusaso beveis chamiv. 
I don't know who says this.
A quibble: when the seder is moztaei Shabbat, there are two more 
brachot said: ner and havdala. However, one may say that these 
brachot, although said at the seder, are not part of the seder per se
A further observation is that this vort goes better according to the 
Sfardic practice, according to which IIUC hagafen is not said over 
the second kos. Otherwise we have 8 brachot, and would have to come 
up with some reason that ine of the brachot  "doesn't count". Maybe 
the origin of the pshat is Sfardic.>

     Havdala should not be considered a problem, since in *most* 
years it is seven brachos.

     The list, however, omits one bracha which all say: al n'tilas 
yadayim.  I think, therefore, that it is an Ashkenazi vort, and that 
the seven brachos are the three of kiddush, ha'adama, asher g'alanu, 
hagefen on the second kos, and n'tilas yadayim.  The motzi and the 
matzo are not counted as brachos that come *before* matza; they are 
the brachos of the matza itself.

EMT