transfer function of cascaded Op Amp?
When two circuits - isolated from each other - form the forward path of a system with feedback, you can multiply the two transfer functions TF=TF1*TF2.

As a second step, the general feedback formula (H. Black) can be applied H(s)=TF/(1-LG). LG is the loop gain (which must be negative for negative feedback).

However, in your circuit, there is no overall feedback at all (the feedback signal is shorted in the signal source Vin)