There really is no substitute for Devonshire cream. But since it’s not easy to find in the United States, this may be the best you can do.
8 oz mascarpone cheese*
½ cup heavy whipping cream
1 tsp sugar
½ tsp lemon juice
½ tsp vanilla
Using a mixer with a whisk attachment on high speed, whip together the cheese and cream in a cold bowl until soft peaks start to form. Add the sugar, lemon juice, and vanilla, and whip until thoroughly combined. Serve alongside fruit jam with traditional scones.
*If you can’t find mascarpone cheese, you can use cream cheese.