Pastry (for 9" tart pan - with removable side)
1/4 cup plus 2 tablespoons sugar
1 2/3 sticks butter - chilled
2 1/2 cups sifted flour
Pinch of salt
1 egg plus 1 yolk (save egg white)
1 tablespoon rum
1 grated lemon rind
3/4 cup sugar
1/4 cup water
Small amount of lemon juice or corn syrup
1/2 cup heavy cream
5 ounces walnuts, coarsely chopped
1 rounded teaspoon honey
1 tablespoon kirsch (optional)
1 egg white
3/4 cup powdered sugar
1/8 teaspoon cream of tartar
In a food processor fitted with the steel blade, place flour, chilled butter cut in 1/2" dice, sugar and salt. Pulse to coarse meal stage. Combine eggs, rum and lemon rind. Sprinkle over mixture and pulse briefly, until blended.
Turn out onto work surface, gather together and work until the pastry holds together. Gather into a ball, cut in half, and shape into disks. Flatten each disk to a 1/2" thick circle. Refrigerate approximately 15 minutes to firm. Roll one disk to 1" larger than the pan. (Rolling between plastic wrap is a good way to do it.) Peel off wrap (refrigerate if sticky) and line pan. Chill until ready to fill. Roll out top pastry to a circle 1/2" bigger than pan. Chill.
In a heavy, fairly deep saucepan that is light in color, place water and sugar (and a little corn syrup or lemon juice). Bring to a boil over low heat, swirling sugar to dissolve. DO NOT STIR. Then raise heat, watch closely and take to a deep golden color. In the meantime, heat cream just until warm. When the caramel reaches the desired color, pour in the warm cream, slowly at first (it will rise in the pan and steam), stirring constantly. Add walnuts, honey and kirsch. Stir and set aside until cool. Pour into pan lined with pastry. Top with the remaining pastry, seal edges, and cut off excess. Brush top with royal icing.
NOTE: I find it works well to add a little corn syrup or lemon to the sugar and water. Some chemical process makes the caramel process more consistent if you do.
Mix egg white, powdered sugar and cream of tartar.
Bake at 350 degrees approximately 45 minutes. Let cool 10 minutes and remove outer ring of tart pan. Continue to cool, remove bottom of tart pan, and wrap in plastic. Can be made ahead. Ages well!