Preheat oven: Set an oven rack in the lower half of the oven. Preheat to moderately slow oven 160°C (320°F).
Line the pan: Lightly grease the base and sides of a 20-cm/8-inch springform pan. Cut a square piece of paper that extends beyond the base by 2 cm (1 inch) and place it over the base. Put the collar back on and close the latch. Line the collar so that the paper extends 3-4 cm above the top of the pan.
Make the biscuit base
In a food processor, combine digestive biscuits and ground cinnamon and process until fine. Add melted butter, and pulse a few times until well combined. Press the mixture into the base of the pan with the back of a spoon.
For a crispy biscuit base: Bake at 160°C (320°F) for 10 minutes. Remove from the oven and set aside - it will crisp up as it cools. For a soft biscuit base: Chill until needed.
Make the cheesecake
Place the softened cream cheese in the mixer bowl of a stand mixer fitted with a paddle attachment. Alternatively, you can use a large mixing bowl and handheld beaters. Beat at medium speed for 15 - 20 seconds to soften the cream cheese.
Add sugar and continue beating until the mixture is smooth, light and free of lumps, about 2 - 3 minutes. Scrape down the sides of the bowl once or twice to ensure a uniform consistency. Tip: Do not overbeat - you don't want the mixture airy or fluffy.
Reduce mixer speed to low. Beat in the eggs until well incorporated. Beat or fold in the sour cream and lemon juice.
Optional (but highly recommended): For an extra smooth and lump-free texture, place a fine-mesh strainer over a clean bowl and strain the cream cheese mixture in batches. The mixture will be thick so use a metal spoon or whisk to press against the wire mesh. Scrape the batter off the bottom of the mesh and into the bowl.
Lastly, fold in the lemon zest (optional) and blueberries.
Pour the cream cheese and blueberries batter into the prepared pan. Tip: If you want a flawlessly smooth top, fill the pan with half of the cream cheese batter, sprinkle the blueberries all over, cover with the remaining batter and smoothen the surface with a spatula.
Bake the cheesecake at a low temperature of 160°C (320°F) for 45 - 50 minutes or until done. Do not open the oven door during baking. Test for doneness: Wearing oven mitts, gently shake the pan. If the edges of the cheesecake are set, and only the center 2 - 3 inches of the cheesecake jiggles or wobbles (without sloshing or breaking the surface like a liquid), it is done.
Turn off the oven, leave the oven door slightly ajar, and let the cheesecake cool in the turned-off oven for 1 hour. When completely cooled, wrap the cheesecake (with pan) in several layers of cling wrap. Chill for at least 4 to 6 hours, preferably overnight, to allow it to firm up and set.
Make the blueberry compote
In a small saucepan set over medium heat, combine blueberries, lemon juice, and sugar. Gently cook the mixture until the blueberries release juices and soften slightly, stirring only occasionally.
Add corn starch slurry bit by bit until the compote reaches the consistency of a thick glaze. Set aside to cool. Note: Do not over-stir or over-cook. Most of the blueberries should still look plump and juicy, not punctured and mushy.
Make the lemon whipped cream
In a chilled mixing bowl, pour in cold heavy or whipping cream. Whip on medium speed until soft peaks, then add the icing sugar. Continue to whip until the whisk or beaters make lines in the cream.
Lower the speed and continue to whip until stiff peaks form. Fold in the lemon juice. Chill until needed.
Decorate the cheesecake
Release the cheesecake from the pan and remove the baking paper. Cover the center with blueberry compote, leaving 1-inch (2-cm) at the edges free.
Fit a piping bag with a piping tip of your choice, and fill it with lemon whipped cream. Pipe the desired pattern all around the edges. Extra lemon whipped cream can be served with blueberry compote on the side with each slice of cheesecake.
1. Biscuits: Sub out the digestives with graham cracker crumbs, sweet biscuits, shortbread cookies, or gingersnap cookies. For warm flavors, add a dash of spices like ground cinnamon, nutmeg, or all-spice. For added texture and nutty flavors, mix in some ground almonds or hazelnuts with the biscuit crumbs.2. Cream cheese: Avoid low-fat cream cheese, cream cheese packed in tubs, or labeled 'spreadable'.3. Sour cream: For the best flavor and that extra creamy texture, use full-fat sour cream. Can be substituted with full-fat plain yogurt or Greek-style yogurt.4. Blueberries: Fresh or frozen or freeze-dried is fine. If using frozen or freeze-dried ones, do not thaw as these can stain the cream cheese batter.