Crush the graham crackers into fine crumbs, then mix them with sugar, melted and cooled butter, salt, and cinnamon in a bowl until the mixture resembles wet sand. Wrap the outside of a 9-inch springform pan with foil (this prevents water from seeping in during the water bath), then press the crumb mixture firmly into the bottom and up the sides of the pan. Bake at 375°F for 8 minutes to set the crust, then remove and set aside while you lower the oven to 325°F. I like to press the crust with the bottom of a measuring cup to get an even, compact layer—this prevents it from becoming crumbly.

Beat the room-temperature cream cheese on medium speed for 1 minute to soften it, then add the sugar and beat for 3 minutes until light and fluffy—this aerates the batter and prevents a dense cake. Mix in the sifted flour, vanilla, lemon juice, and lemon zest until just combined. Add the eggs and egg yolks one at a time, beating on low speed after each addition just until incorporated (overmixing at this stage introduces too much air and can cause cracks). Finally, gently stir in the sour cream and 5 oz of huckleberries by hand—folding is better than beating here to keep the batter smooth and prevent excess air incorporation.

Pour the batter from Step 2 into the prepared crust from Step 1. Place the springform pan inside a larger roasting pan, then add about 1 inch of boiling water to the roasting pan around the cheesecake (the water bath ensures gentle, even heat distribution and prevents cracking). Bake at 325°F for 90-100 minutes—the cheesecake is done when the edges are set but the center still jiggles slightly when gently shaken, about a 2-inch diameter circle in the very middle. I always use an instant-read thermometer to check for doneness: the center should read 150°F.

Turn off the oven and crack the door open about 4 inches, then let the cheesecake cool in the oven for 1 hour. This gradual temperature change prevents the cake from contracting too quickly, which causes deep cracks on the surface. After 1 hour, remove the cheesecake from the oven and let it cool to room temperature on the counter (about 1-2 hours), then refrigerate for at least 4 hours or overnight before serving.

Combine 10 oz of huckleberries, sugar, and water in a saucepan and bring to a boil over medium-high heat, then reduce to a simmer and cook for 10 minutes until the berries soften and release their juices. In a small bowl, whisk together the cornstarch and lemon juice to create a slurry, then stir it into the simmering berries. Cook for 1-2 minutes more, stirring constantly, until the mixture thickens and becomes glossy and translucent. Remove from heat and let cool to room temperature—the topping will thicken further as it cools.

Once the cheesecake is fully chilled, run a thin knife around the edge to loosen it from the pan, then carefully remove the springform ring. Spoon or spread the cooled huckleberry topping from Step 5 evenly over the top of the cheesecake just before serving. Slice with a hot, wet knife (wipe between cuts) to get clean slices without cracking the topping.