In a large skillet over medium heat, cook the chopped bacon until crispy, about 5-7 minutes. Remove the bacon from the skillet and set aside, leaving the drippings in the pan.
Add the sliced onions to the skillet and sauté in the bacon drippings for about 3-4 minutes until they become translucent.
Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the sliced summer squash to the skillet, along with the salt and black pepper. Drizzle with olive oil and stir well to combine.
Sauté the mixture for about 5-7 minutes, or until the squash is tender but still slightly crisp.
Return the cooked bacon to the skillet and mix everything together. Cook for another 1-2 minutes to heat through.
Remove from heat and garnish with fresh parsley before serving.