In a shallow dish, whisk together the flour, cornstarch, baking powder, garlic salt, and smoked paprika.
Lightly dredge the chicken tenderloins in the flour mixture and set aside.
In a separate shallow dish, combine the milk with 1 tbsp. of the flour mixture and whisk to blend.
Dip each floured chicken tender into the milk mixture, then dredge it again in the flour mixture to coat fully. Set aside.
In a large frying pan, heat the oil over medium-high heat until it reaches 350°F.
Fry the chicken tenderloins in batches, being careful not to overcrowd the pan. Cook for 2-3 minutes per side, until golden brown and crispy.
Transfer the fried chicken to a paper towel-lined plate or wire rack to drain excess oil.
To prepare the sauce, melt the butter in a medium skillet over medium heat.
Whisk in the flour and cook for 2 minutes to form a roux.
Gradually whisk in the chicken stock until smooth and lump-free.
Add the heavy cream, sugar, minced garlic, Italian seasoning, lemon juice, and red pepper flakes. Bring the mixture to a gentle bubble, stirring occasionally, until the sauce thickens slightly.
Stir in the grated Parmesan cheese until melted and smooth.
Dunk the crispy chicken tenders into the sauce or drizzle the sauce generously over the top.
Serve warm and enjoy!