Prep your pan and oven. Heat the oven to 325°F (163°C).
Line the bottom of an 8- or 9-inch springform pan with parchment and lightly grease the sides. This prevents sticking and keeps the crust crisp.
Make the crust. In a bowl, mix 3/4 cup oat flour (or blend rolled oats to flour), 1/2 cup almond flour, 1 scoop vanilla protein powder, 1 teaspoon cinnamon, a pinch of salt, 2 tablespoons melted light butter or coconut oil, and 1–2 tablespoons maple syrup or sweetener. The mixture should clump when pressed.
If too dry, add a splash of milk.
Press and par-bake. Press the crust firmly into the pan. Bake for 8–10 minutes until lightly set. Remove and let it cool while you prepare the filling.
Mix the cinnamon swirl. In a small bowl, combine 2 tablespoons brown sugar (or substitute), 2 teaspoons cinnamon, and 1 tablespoon melted butter or oil.
Set aside.
Blend the filling base. In a large bowl, beat 16 ounces light cream cheese until smooth. Add 1 cup Greek yogurt, 2 scoops vanilla protein powder, 1/2–3/4 cup granulated sweetener (adjust to taste), 2 teaspoons vanilla, 1 tablespoon lemon juice (optional), and a pinch of salt. Mix on low until combined.
Add the eggs gently. Beat in 2 large eggs, one at a time, on low speed. Do not overmix—this traps air and can cause cracks.
Layer and swirl. Pour half the filling over the crust.
Drizzle half the cinnamon mixture in thin ribbons. Add the rest of the filling, then drizzle the remaining cinnamon mixture. Use a knife or skewer to create gentle swirls. Avoid over-swirling so the pattern stays defined.
Bake low and slow. Place the pan on the middle rack.
Bake 35–45 minutes, until edges are set and the center still has a slight wobble. If your oven runs hot, tent the top with foil for the last 10 minutes to prevent over-browning.
Cool gradually. Turn off the oven, crack the door, and let the cheesecake rest inside for 30 minutes. Transfer to the counter to cool to room temp, then refrigerate at least 6 hours (overnight is best).
This sets the texture and locks in creaminess.
Make the glaze. Whisk 1/3 cup powdered sugar or sweetener with 1–2 teaspoons milk until smooth and thick but pourable. Drizzle over the chilled cheesecake in classic cinnamon roll stripes.
Slice and serve. Run a warm knife around the edge, release the springform, and slice. For clean cuts, wipe the knife between slices.
Enjoy chilled or slightly cool.