Turn the oven to 375
Dice the onions, and cut the bacon into 1/4 inch pieces.
Chop the rosemary finely. I often cut it off the branch with scissors.
Fry the onions, bacon, garlic and rosemary until the onions are translucent and beginning to brown. Remove from heat and set aside to cool.
Remove the sausage casings if your sausage is cased. Mix everything together in a large bowl with your hands or the flat paddle on a KitchenAid mixer.
Make 1 to 1 1/2 inch balls with your hands and add to a foil lined baking tray. Bake in the oven (turning every 5 minutes or so) until the balls are browned and reach an internal temperature of 160 degrees farenheight.
Frequent turning ensures an even browning and prevents the balls from sticking to your baking tray.
Balls can be made in advance and reheated just prior to serving. Leftovers are to be encouraged, see above.