Smoke bratwursts (if not already smoked).

Cut smoked bratwursts diagonally into bite-sized pieces.

Finely chop garlic.

Thaw frozen spinach.

Chop yellow onion into 3/4 inch squares.

Slice mushrooms.

Melt butter in a large saucepan over medium heat.

Add garlic and salt to the melted butter and sauté until the butter just starts to turn brown.

Add onions and cook until soft.

Add mushrooms and cook until softened.

Gently stir in spinach, olive oil, lemon juice, pepper, and bratwursts.

Turn heat to low, cover, and simmer while preparing the pasta.

Prepare pasta according to package instructions.

Drain the pasta once cooked.

Fold the cooked pasta into the spinach mixture thoroughly.

Serve immediately. Consider adding grated Parmesan cheese or crushed red pepper flakes for extra flavor.