Grind the beef or pork liver and garlic cloves together using a meat grinder or food processor until smooth. Mix in the 4 eggs and flour. Season with salt and pepper. If the dough is too firm, add a dash of beef broth to loosen it. Let the mixture rest for 30 minutes at room temperature.
Bring a large pot of salted water to a boil over medium-high heat. Using a spaetzle sieve, press the dough in small portions into the boiling water. When the spaetzle float to the surface, cook for another 2 minutes. Remove with a colander and drain well.
Divide the cooked spaetzle between soup bowls. Pour the hot beef broth over the spaetzle and serve immediately.