Choose a full-flavored baking apple, and one that won't fall apart once baked. A trip to the apple stand at your farmers' market would be a good place to get advice about a local variety that's good for baking. You want one that's full-flavored, and to my taste, on the tart side. (If you like sweet apples, you could certainly use those.) I offered up a few varieties that are widely available in the post. To dial down the richness, you can swap out half-and-half for the cream in the recipe. Calvados is apple brandy from Normandy. You can substitute another apple brandy. If they're not available, you can use brandy, Cognac, or dark rum. If avoiding alcohol, omit the brandy and double the vanilla extract, although the tart gets its name, and flavor, from the brandy, so the taste will be different.