Some days ago I didn't have what it takes to make a moussaka, but I did
have the eggplants that needed to be used and some ground beef. My
recipe ended up something like this (for 2 people). It felt very fresh
and I'll do it again some time:

1-2 Sliced up eggplant, browned in olive oil. Put aside.

Meat sauce:
Slice 2 onions, saute in olive oil.
When they are soft, add the ground beef and 3-4 cloves of diced garlic,
sprinkle with salt, pepper, cumin, a little chili powder. Brown it about
5 minutes and then add about 10 halved cherry tomatoes. Take it off when
they have softened up a bit.

Meanwhile make the bechamel wannabe in a pot:

Melt some butter, stir in 1 spoonful of flour. When there are no lumps
add some (about 1 cup) of creme fraiche or sour cream. It will be a
little thick so you need to soften it up a bit with milk. Spice with
salt and nutmeg. When it was boiled 2 minutes and has the not too thick
texture, beat in 2 eggs.

Now assemble the moussaka in a deep dish: start with a layer of
eggplant, then all the meat sauce, then eggplants and finally the
bechamel wannabe.
Bake it 20 minutes at 400F/200C.
If you have it, you can slice tomatoes and put them on top and sprinkle
some grated cheese.