the ultimate savory pie crust dough (see note),1/2 cup crème fraîche,1/4 cup grated pecorino romano cheese,1 medium red potato, very thinly sliced, preferably on a mandoline,1 granny smith apple—halved, cored and very thinly sliced, preferably on a mandoline,melted unsalted butter, for brushing,1 teaspoon thyme leaves,salt,freshly ground pepper,1 large egg beaten with 1 tablespoon of water" data-content_ad_keys="" data-content_published_date_formatted="20131206" data-content_modified_date_formatted="20160209" data-content_source="0" data-submission_type="editorial" data-content_syndicated="all" data-content_syndicated_brand="" data-content_syndicated_url="" data-content_nlp_sentiment_label="positive" data-content_nlp_sentiment_score="0.1" data-content_nlp_sentiment_magnitude="3.9" data-content_nlp_entities="red potato|apple galette|crème fraîche" data-content_nlp_categories="/food & drink/food/baked goods|/food & drink/cooking & recipes" data-adtaxonomy="11721,16426,11710,11053,10444,11374,11904,32452,12291,11098,13476,10627,11807">
