01 -
In a large bowl, whisk together the flour and salt. In a separate measuring jug, whisk the water, milk, and eggs until smooth. Combine both mixtures, stirring and beating vigorously for about 5 minutes until no lumps remain, air bubbles form, and the batter rips off the spoon. Cover and let the batter rest for 30 minutes.
02 -
Bring a large pot of salted water to a boil, then reduce to a good simmer. Place a wooden board on top of the pot and drop ½ cup of batter onto the board. Using a blunt knife, scrape small portions of batter into the water. Once the spaetzle float to the surface, remove them with a slotted spoon and transfer to a lightly buttered casserole dish to keep warm. Repeat with remaining batter.
03 -
While the batter is resting, place a large skillet over medium-high heat and melt half of the butter. Add the onion, garlic, and mushrooms, cooking until the mushrooms are softened (about 5–10 minutes).
04 -
Reduce the heat to medium. Sprinkle the thyme, salt, pepper, and flour evenly over the mushrooms, stirring well. Add the tomato paste and mix. Deglaze the pan with white wine, scraping off browned bits, and then add the beef broth. Simmer for 10–15 minutes until thickened. Finish with heavy cream if desired. Serve the warm gravy over the spaetzle.