Preheat your oven to 350°F (175°C). In a large mixing bowl, cream together softened unsalted butter and granulated sugar until fluffy, about 2-3 minutes.

Add the egg and vanilla extract, mixing until well combined.

In another bowl, whisk together all-purpose flour, baking powder, and salt. Gradually add the dry mixture into the wet ingredients, combining until a dough forms.

Press this dough evenly into a 9-inch springform pan and bake for 10-12 minutes, or until the edges are golden brown. Allow to cool.

In a clean mixing bowl, beat softened cream cheese with an electric mixer on medium speed until smooth and creamy, approximately 2-3 minutes.

Gradually add granulated sugar and vanilla extract, mixing until combined. Incorporate eggs one at a time, mixing until each is fully combined.

If using sour cream, gently fold it in along with a little flour until creamy.

Once the crust has cooled, pour the cheesecake filling over it and smooth the top.

Lower oven temperature to 325°F (163°C) and bake the cheesecake for 40-50 minutes.

Once finished, cool at room temperature for 30 minutes, then refrigerate for 3-4 hours or overnight.

Garnish with whipped cream, sugar sprinkles, and fresh berries before serving.