Heat a medium saucepan over low heat and melt the butter. Stir in the garlic and cook 3 minutes, until slightly softened and very fragrant.
Increase the heat to medium and slowly stir in the half-and-half. Season with salt and pepper.
Bring to a slight simmer (not a boil) and cook 1 minute, stirring constantly.
Reduce the heat to low and stir in the cheese and chopped thyme. (If not ready to use, remove from the heat and cover, then gently rewarm.)
Boil the farfalle in boiling, salted water about 10 minutes. Drain.
Heat a large, deep skillet over medium heat and add the olive oil. Add the onion and turkey and season with salt and pepper. Cook until the onion has softened and the turkey is just cooked through, about 5 minutes.
Add the spinach and white wine. Cook until the spinach has wilted and the mixture has reduced slightly, 3-4 minutes.
Pour the alfredo into the turkey mixture and stir gently to combine. Add the cooked pasta and toss well to coat.
Divide the farfalle in alfredo among 4 pasta bowls and serve right away.