Preheat oven to 400 degrees F.
Heat oil over medium-high heat in a large, oven-safe skillet.
Once warm, add sausage and break it up with a wooden spoon or potato masher into small pieces. Cook until browned and cooked through, about 4-5 minutes.
Add onions and cook until they begin to sweat out, about 3-4 minutes.
Add garlic, oregano, red pepper flakes and salt and cook, stirring often, until garlic just begins to brown, about 2 minutes.
Add chicken stock and cook until it’s reduced by half.
Add peppers and stir to combine.
Add tomatoes and using the same wooden spoon or potato masher, carefully crush the tomatoes in the pan.
Reduce heat to medium and simmer, stirring occasionally, for 10 minutes.
Stir in the spinach and simmer for an additional 10 minutes.
Remove from heat and crack each egg over the tomato sauce. Season with salt and pepper and careful transfer the skillet to the oven.
Cook until the egg whites are set, about 12-14 minutes.
Preheat broiler. Place bread halves on a baking sheet and broil bread until very toasty and charred.
Remove from oven and using 1 garlic clove per side of bread, rub the garlic along the bread.
Dress with extra-virgin olive oil and cut into 6 pieces.
Garnish the skillet with basil.
Using a serving spoon, spoon 1 egg with all the sauce underneath it into a shallow bowl and serve with a slice of garlic toast.