RHUBARB-FLAN TARTS

Steps:

• Tie the cinnamon, clove, mace, and mustard seeds in a few layers of cheesecloth. Put the spice sachet in a saucepan with the wine and vinegar and bring to a boil over medium heat. Add the rhubarb, bring to a simmer, and simmer for 5 minutes. Remove from the heat and let cool to room temperature.
• Drain to get rid of the excess liquid. Remove the spice sachet and puree the rhubarb in a food processor.
• Set up an ice bath in a large bowl.
• Bring the rhubarb back to a simmer. Mix the sugar and xanthan gum and whisk in, a few grains at a time (you don't want the xanthan gum to clump). Scrape out into a medium bowl and set into the ice bath, stirring often to chill down quickly. Once cool, refrigerate until ready to serve or for up to 1 week.
• Peel the rhubarb and cut into tiny dice. Toss it with the sugar and macerate for at least 2 hours.
• Set up an ice bath in a large bowl.
• Put the cream and vanilla seeds (rinse, dry, and save the pod for another use) in a small saucepan and heat to just below a simmer.
• Whisk the sugar and cornstarch together.
• In a separate bowl, whisk the egg until smooth; gradually whisk in the dry ingredients, beating until smooth.
• Slowly add half the warm cream to the egg mixture and whisk for about 1 minute to temper it. Off of the heat, scrape the egg mixture into the pan and mix well with an immersion blender. Strain into a small bowl and set into the ice bath to chill down quickly, stirring often. Refrigerate until ready to use or for up to 1 day.
• Roll half the dough 1/16 inch thick on a lightly floured work surface. Transfer to a Silpat- or parchment-lined baking sheet and chill for 30 minutes. Cut out eight 2 1/4 x 4-inch rectangles and line eight 3/4 x 3 1/4-inch tart molds with the dough (or cut 3 1/2-inch circles and line 2 1/4-inch tart rings). Place them on the baking sheet and chill for 30 minutes.
• Heat the oven to 375°F or 350°F on convection.
• Strain the rhubarb filling and fill the tart shells to overflowing. Bake until the rhubarb is starting to brown, about 20 minutes.
• Reduce the oven temperature to 325°F (300°F if you're using convection).
• Pour some of the flan into each tart and top each with a generous amount of the graham streusel. Bake until the streusel is browned and the filling is bubbling, about 20 minutes.
• Let cool for at least a few minutes before unmolding. You can serve the tarts warm or at room temperature.
• Spoon some mustard-rhubarb jam onto dessert plates and spread it with the back of a spoon. Dust the tarts with confectioners' sugar, set them on the jam, and serve.
• Try making this as a single large tart in a 9-inch tart pan. You could doctor some good all-fruit jam from the grocery store with crushed mustard seeds instead of making the jam.