How to Make It
Preheat oven to 450°F. Place bread in a bowl; add ⅓ cup water and press to help bread soften. Let stand for 5 minutes.
Place beef in a large bowl and make a well in the center. Add ham, ricotta, pecorino Romano, onion, salt, oregano, fennel seeds, pepper, eggs, and bread mixture. Using a rubber spatula, mix ingredients together in the center of the well, gradually incorporating beef, working from the center outward and mixing until just incorporated. (Do not overmix.)
Brush 2 baking sheets with oil. Shape beef mixture into balls (about 1 tablespoon each) and place 1 inch apart on sheets.
Bake until meatballs are golden on bottoms, about 10 minutes. Flip and continue baking until golden brown and cooked through, 10 to 12 minutes more.
To freeze, let cool completely before storing in airtight containers. Freeze for up to 3 months. Thaw in the refrigerator overnight or in the microwave on high for 2 minutes.