How to assign very large outputs to function for evaluation at points?

I create a very large output

    D(x^100*E^(2*x^5)*Cos(x^2), {x, 137})

I want to assign this to a function as

    f(x_):= {very large output from previous command}

This allows me to evaluate that output for various values of $x$.

I tried

    Function(x, Evaluate(%11))

But it seems cumbersome and I wasn’t sure I was getting correct results from it.

Is there a clean way to do this?