Place a rack in the center of the oven and preheat to 350 degrees F. Melt the butter in a medium, microwave-safe bowl, or melt it on the stove and transfer it to a bowl. Place a 9-inch springform pan on a rimmed baking sheet. Brush a little of the melted butter on the insides of the pan, reserving the rest in the bowl.
Prepare the crust: Add the graham cracker crumbs, 2 tablespoons sugar, and salt to the bowl with the melted butter. Stir until evenly moistened, then pour into the prepared pan. With your fingers, press the crumbs into an even layer along the bottom and 1 inch up all sides. Bake for 8 minutes, until the crust is lightly golden and fragrant. Remove the pan from the oven, transfer the springform pan to a wire rack, and let the pan cool to room temperature. (Once the pan has cooled a bit, you can also place it in the refrigerator or freezer to speed along the cooling process). Reduce the oven temperature to 325 degrees F.
Prepare the cheesecake filling: In a food processor fitted with a steel blade, combine the Greek yogurt and cream cheese. Once they are partly combined, add the 3/4 cup sugar and blend until perfectly smooth and blended. Scrape down the bowl then add the eggs, one at a time, blending between each. Once the eggs are incorporated, scrape down the bowl again. Sprinkle in the flour, vanilla extract, and lemon zest. Process until very smooth, creamy, and completely blended, stopping to scrape down the bowl as needed. Pour the batter into the cooled crust and smooth the top. Place the springform pan back on the rimmed baking sheet. Bake at 325 degrees F in the in center of the oven for 45 to 55 minutes, until the cheesecake is set around the edges but 2 to 3 inches in the middle still wiggle a little bit when you move the pan. The center should jiggle like Jell-O but not be moving like a wave.
Remove the cheesecake pan from the baking sheet and place the pan on a wire rack. Let the cheesecake cool COMPLETELY at room temperature, at least 2 to 3 hours. Once it has reached room temperature, cover the top of the pan with plastic and place it in the refrigerator. Let cool an 8 additional hours or overnight.
Meanwhile, prepare the strawberry topping: Place the cornstarch and 1/4 cup water in a medium saucepan. Stir to completely dissolve. Add the strawberries, 3 tablespoons sugar, and lemon juice to the pan and turn the heat to medium. With a wooden spoon or rubber spatula, stir the mixture and continue to heat. Break up the some of the strawberries as you stir, leaving them a little chunky. Bring the mixture to a simmer and let simmer for 5 minutes, stirring constantly. Remove the pan from the heat and let cool. The mixture will continue to thicken.
When ready to serve, run a knife under hot water, wipe it dry, then run it around the outside edges of the cheesecake to loosen it from the pan. Carefully remove the outside of the pan. Slice and serve with the strawberry topping.
Having all of the ingredients at room temperature is NOT optional. If any of the ingredients (yogurt, cream cheese, eggs, etc.) are cold, the cheesecake will not be smooth. Your patience will be rewarded!
Prepare the crust and filling up to 1 day in advance. Store separately in the refrigerator, then pour the filling into the crust and bake as directed. The entire baked cheesecake can be prepared and stored up to 1 day in advance. Leftovers will keep in the refrigerator for 2 to 3 days.
To freeze: Cover the baked cheesecake tightly and freeze for up to 2 months. Let thaw overnight in the refrigerator before serving.
Leftover strawberry topping can be stored in the refrigerator for up to 2 weeks. Any extra is delicious over vanilla ice cream, brownies, oatmeal, or Greek yogurt with fruit and granola.