Cook bacon in a large skillet until crisp; remove bacon, and drain on paper towels, reserving 2 tablespoons drippings in skillet.
Crumble bacon; set aside.
Sauté onion in hot drippings 2 to 3 minutes or until tender.
Set aside.
Combine baking mix and next 3 ingredients in a large bowl; make a well in center of mixture.
Whisk together 1 cup milk and eggs; add to cheese mixture, stirring just until dry ingredients are moistened.
Stir in bacon and onion.
Spoon batter into lightly greased miniature muffin pans, filling two-thirds full.
Bake at 425° for 18 minutes or until muffins are golden.
Remove muffins from pans.
Serve muffins warm, or let them cool on wire racks.