Design Lowpass Filter With -7.5 dB/Octave Rolloff

I am working on a project that needs a lowpass filter with a -7.5 dB/Octave rolloff. This is somewhere between the rolloff of a one-pole and two-pole filter, so I wanted to ask what some standard methods are for generating this type of response.

Is it appropriate to have a two pole filter (or two one-pole filters in series) and do a wet/dry mix? Or would is there a more robust method I should try instead?

I am hoping I am able to accomplish this using a simple IIR filter like a biquad.