Pecan filling:
8 tablespoon unsalted butter, cut into tablespoons
2 tablespoons honey
2 tablespoons granulated sugar
1/2 cup light brown sugar
1 cup pecan halves
2 tablespoons heavy cream

Chocolate topping:
1/2 cup heavy cream
1 tablespoon granulated sugar
2/3 cup semisweet chocolate chips

Garnish:
1 ounce white chocolate, coarsely chopped
8 pecan halves

Make the shortbread crust:
1. Position a rack in the center of the oven and preheat to 350 degrees F.
2. Into a medium bowl, sift together the flour, salt and baking powder.
3. In a medium bowl, using a hand-held electric mixer, cream together the butter and sugar until light and fluffy. Add the egg and vanilla and mix at low speed until combined. While continuing to mix at low speed, add the flour mixture in three batches, mixing just until the dough starts to come together.
4. Scrape the dough into a 9 1/2-inch fluted tart pan with a removable bottom. Using your fingertips, press the dough evenly into the bottom and
up the side of the pan. Set the crust aside.

Make the pecan filling:
5. In a small saucepan, place the butter, honey, sugar and brown sugar. Cook over medium-high heat, stirring constantly, until the mixture comes to a boil. Continue to boil the mixture for 3 minutes. Remove the pan from the heat and stir in the pecan halves. Stir in the cream. Pour the pecan mixture into the prepared crust and bake for 30 minutes. Cool the tart on a wire rack for
1 hour.

Make the chocolate topping:
6. In a small saucepan, combine the cream and sugar. Cook over medium-high heat, stirring occasionally, until the mixture comes to a boil. Remove the pan from the heat and stir in the chocolate chips. Whisk the mixture until smooth. Set aside 1/3 cup of the topping in the refrigerator for garnish.

Garnish the shortbread:
7. Pour the warm chocolate topping over the top of the tart and spread it evenly with a small metal cake spatula.
8.Place the tart uncovered in the refrigerator for 15 minutes to set the chocolate.
9. Place coarsely chopped white chocolate in the top of a double boiler over hot, not simmering, water. Melt the chocolate, stirring until smooth. (Chocolate that has been overheated may scorch, lose flavor and turn coarse and grainy. Stir melting chocolate after it has begun to liquefy. Because of the sensitivity of milk solids to heat, milk and white chocolates should be stirred almost constantly while dark chocolate need only be stirred frequently during melting.) Fill a small parchment cone with the melted chocolate. Pipe the chocolate in fine lines across the top of the tart in a crisscross pattern.
10. Fill a pastry bag fitted with a medium star tip (such as Ateco #5) with the reserved chocolate topping. Pipe 8 rosettes around the edge of the tart. Top each rosette with a pecan half.