01 -
In a large bowl, gently mix the ground beef, breadcrumbs, egg, a pinch of salt, and a good crack of black pepper. Don't overmix, hon, that's how you get tough meatballs! I usually just use my hands; it feels more intuitive. Form them into about 1.5-inch balls. I sometimes get a little messy here, with bits of beef clinging to my fingers – it’s all part of the process, right? You should feel them just come together, not compacted.
02 -
Heat a large skillet over medium-high heat with a little olive oil. Once shimmering, carefully place the meatballs in a single layer, working in batches if needed, making sure not to crowd the pan. Sear them until beautifully browned on all sides, about 2-3 minutes per side. This step is non-negotiable for that deep, savory crust! The kitchen will start to smell amazing already, a hint of the deliciousness to come. Remove them and set aside.
03 -
In the same skillet (don't clean it, those browned bits are flavor!), add a bit more olive oil if needed, then toss in your thinly sliced yellow onions. Reduce the heat to medium-low. This is where patience is your friend, to be real. Stir occasionally, letting them slowly soften and turn a gorgeous golden-brown, about 20-25 minutes. They should smell sweet and deeply aromatic, filling your kitchen with that classic French onion scent.
04 -
Once the onions are perfectly caramelized, stir in the minced garlic and fresh thyme for about a minute until fragrant. Then, sprinkle in the flour and cook for another minute, stirring constantly. Pour in the beef broth and red wine (if using), scraping up any browned bits from the bottom of the pan – this is pure flavor, honestly! Bring it to a gentle simmer, letting the sauce thicken slightly.
05 -
Carefully transfer the seared meatballs and the luscious French onion sauce to your slow cooker. Give it a gentle stir to make sure the meatballs are nestled in the sauce. Cover and cook on low for 3-4 hours or on high for 2-3 hours, until the meatballs are tender and cooked through, and the sauce has deepened in flavor. I always peek in around the 3-hour mark on low, just to check on my little meatball buddies.
06 -
Once cooking time is up, give the sauce another taste and adjust seasonings if needed. I sometimes add a touch more salt or pepper here. To serve, ladle the Crock Pot French Onion Meatballs into bowls, then generously sprinkle with freshly grated Gruyere cheese and a final flourish of fresh thyme. Watch that cheese melt and get all gooey – it's pure comfort, I promise!