Wash the pork tenderloin and pat dry. Season with salt and pepper. Heat oil in a pan. Brown the meat in it all around, take it out and put it on the fat pan of the oven.
Continue roasting in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Peel onions and cut into thin rings. Dice bacon. Clean broccoli, divide into small florets and wash.
Put broccoli in boiling salted water and cook for about 8 minutes. Heat the frying fat. Fry the bacon in it. Add onions, fry for about 3 minutes, dust with flour. Add stock and cream and boil up while stirring.
Season to taste with salt and pepper. Keep sauce warm. Leave the pasta to stand in boiling salted water for about 1 minute, pour onto a sieve and drain. Drain broccoli. Arrange spaetzle, meat, broccoli and sauce on plates.