Pat chicken cutlets completely dry with paper towels. Season both sides with sea salt and black pepper, then lightly dredge in flour, tapping off all excess so only a sheer dusting remains.
Heat 2 tablespoons olive oil and 1 tablespoon butter in a large deep skillet over medium-high heat until hot and shimmering.
Add chicken cutlets in a single layer without crowding. Sear undisturbed for 3 to 4 minutes until golden-brown and crisp, then flip and sear for 3 minutes on the second side until cooked through (165°F / 74°C). Transfer to a warm plate.
Reduce skillet heat to medium. Add minced garlic and cook for 30 seconds until fragrant. Pour in chicken broth to deglaze the pan, stirring to dissolve the savory browned bits.
Pour in the heavy cream, freshly grated parmesan cheese, dried oregano, and crushed red pepper flakes. Whisk gently and simmer for 2 to 3 minutes until the sauce thickens into a glossy cream.
Stir in the julienned sun-dried tomatoes and baby spinach, cooking for 1 minute until the spinach wilts into tender ribbons.
Nestle the seared chicken cutlets back into the skillet, spooning the luscious sauce over each piece. Simmer for 1 minute to warm through. Garnish with fresh basil and serve immediately!