John Gill Commentary Numbers 28:5

"and the tenth part of an ephah of fine flour for a meal-offering, mingled with the fourth part of a hin of beaten oil." — Numbers 28:5 (ASV)

And the tenth part of an ephah of flour for a meat offering , &c.] Which always went along with the burnt offering:

mingled with the fourth part of an hin of beaten oil : which in those times and countries was used instead of butter; and fine flour and this mingled together made a "minchah", or bread offering, as it should rather be called; of the measures used, (See Gill on Exodus 29:40).