I've listened again, this time with earphones, and the word I couldn't get is bread, simply bread, thus the line is: "Black-eyed peas and bread and butter". Still, I'm not sure of the 4th stanza. R

Mr. Frog went a-courtin', he did ride, mm, mmm
Mr. Frog went a-courtin', he did ride
A sword and a pistol by his side, mm, mm

He went up to Miss Mousie's door, mm, mmmm
He went up to Miss Mousie's door
He rapped so loud till he made it roar, mm, mm

Oh Miss Mouse, are you within? - mm, mmmm
Oh Miss Mouse, are you within?
Yes, kind sir, I card and spin, mm, mmmm

Miss Mousie, will you marry me? - mm
Miss Mousie, will you marry me?
Yes, kind sir, just you (?) wait and see, mm, mm

Where shall the wedding be? - mm, mmmm
Where shall the wedding be?
Away down yonder in the hollow tree, mm, mm

Now, what shall we have for the wedding supper? mm
What shall we have for the wedding supper?
Black-eyed peas and bread and butter, mm, mmm

Mr. Froggie went a-swimming 'cross the lake, mm, mm
Mr. Froggie went a-swimming 'cross the lake
He got swallowed by a big black snake, mm, mmm

Now, this was an end to the one, two, three, mm, mmm
This was an end to the one, two, three
The frog and the flea and the bumble-bee, mm, mm