Fill a large stockpot with salted water and bring to a rolling boil. Add rigatoni and cook 1 minute less than package directions for al dente texture, about 9-11 minutes. Reserve 3/4 cup pasta cooking water before draining.

Meanwhile, heat avocado oil in a heavy-bottomed skillet over medium-high heat. Add chopped sweet onion and sauté for 4-5 minutes until golden and softened. Add pressed garlic and cook 45 seconds until aromatic.

Increase heat to high and add ground turkey, breaking apart with a wooden spoon. Cook 7-9 minutes until turkey is golden brown and reaches 165°F internal temperature. Don't stir too frequently to achieve good browning.

Add chopped sun-dried tomatoes, oregano, and red pepper flakes to the turkey mixture. Pour in chicken stock and bring to a vigorous simmer. Cook 4-5 minutes until liquid reduces by half.

Lower heat to medium-low and add ricotta cheese in small spoonfuls, whisking constantly to prevent lumps. The mixture should become creamy and smooth. Remove from heat immediately once combined.

Add drained rigatoni to the skillet and toss vigorously to coat. Add pasta water gradually, 2-3 tablespoons at a time, until sauce coats pasta beautifully. Fold in Romano cheese and season with salt and white pepper.