Infuse 1/2 cup of the heavy cream by warming it gently until steaming. Remove from heat, add ground Earl Grey tea and lavender. Steep covered for 20-30 mins. Strain and cool to room temperature.

Preheat oven to 400°F (200°C). Line a 9-inch springform pan with two large, crinkled pieces of parchment paper, covering the bottom and sides. Place on a rimmed baking sheet.

In a stand mixer, beat softened cream cheese until completely smooth, about 3-4 minutes. Scrape bowl.

With mixer on low, gradually add sugar. Increase speed to medium and beat for 2-3 minutes until smooth. Scrape bowl.

Add eggs one at a time on low speed, mixing just until each is incorporated before adding the next. Scrape bowl.

To the infused cream, add the remaining 1.5 cups plain heavy cream and vanilla. With mixer on low, slowly pour into cheesecake batter. Mix just until combined.

Sift flour and salt over the batter. Mix on low speed just until no dry streaks remain.

Pour batter into prepared pan. Bake for 50-65 minutes, until top is very dark but the center still has a pronounced jiggle.

Turn off oven, crack door, and let cheesecake cool inside for 1 hour. Then remove to a wire rack to cool completely to room temperature. Refrigerate uncovered overnight.

For sauce: Combine blackberries, sugar, lemon zest/juice, and water in saucepan. Cook over medium heat 8-10 mins until berries break down. Mash to desired consistency.

Bring sauce to a simmer. Stir in cornstarch slurry. Cook 1-2 mins until glossy and slightly thickened. Remove from heat and cool completely. Refrigerate.

To serve, remove cheesecake from pan and parchment. Slice with a hot knife. Serve each slice with a generous spoonful of blackberry sauce.