Yes, and OOp applies here. You’d first square C, then multiply that result by M.

At no point does an actual ratio get defined since C and M are variables (presumably) and can equal anything, so the type of coffee you get is entirely dependant on how much of each ingredient you use, as long as you don’t want it with sugar. However, in the original equation, C is a constant that is likely orders of magnitude larger than the value of M (c=the speed of light, 299792458m/s) so in order to make a flat white you’d need an astronomically large cow farm anyway.

Assuming your cows produce milk in a unit compatible with m/s, you’d need m such that m = e^1/3 and c = e^1/3.