My miele espresso maker dispenses too much water in my espresso. how do I fix this?

If you fill two esspresso cups at the same time it should be the correct size. But if it is weak, see below...
For one cup, press the small coffee button to start. Press the button again when the desired amount of espresso is in the cup to stop the flow. if it is too watery but the correct amount see below.

If the espresso is too weak push the coffee grinds slide switch inside one notch finer and make another 3 cups. If the flavor does not get strong in 3 cups then there is an anomaly happening. The brew unit upper filter has gunk clogged behind it to a point where the pressure (230psi) of hot water trying to get through the gunk pierces a small channel through only a portion of the filter screen. All the water is running through only 4 or 5 holes in the filter screen. This eddy allows hot water to pass most of the grinds without extracting flavor. It's the same as if you clogged a sink strainer then pushed the blockage off part of the strainer. The water goes around the coffee not through it. The path of least resistance.

Remove the upside down stainless steel filter on the brew unit- Remove the screw using the allen key that came with the machine. It goes through the little finger nut on the top of the brew unit. Turn it counter-clockwise (lefty loosy) and the filter will come off from underside. The area behind the filter screen has to be cleaned of any coffee residues. Also check thew creme valve. It is under spring tension accessible from the top of the brew unit by removing two screws holding the long pipe on top. be careful not to let the spring shoot out and loose the creme valve. It looks like a plastic rivet on the other end of the spring. Clean out the entire channel by rinsing. Use a pipe cleaner for dried on grinds.

Note: the finer you set the grinds the quicker it clogs the filters. Increase the use of cleaning tablets when you grind finer coffee. A clogged brew unit is almost impossible to clean even for the most handy of people and the last I checked a new brew unit is well over 200 bucks! Good luck!