01 -
Mix powdered sugar with the soft butter in a bowl. Throw in the ground toasted hazelnuts and salt, stirring until well combined. Add the beaten egg gently, then dump in the plain flour. Keep mixing until you get a nice smooth dough. Wrap it up and stick it in the fridge for at least 2 hours.
02 -
Roll out your cold dough to about 1/8 inch thickness. Cut it into circles roughly 4 1/2 to 4 3/4 inches across. Put the dough into greased and floured tartlet tins (around 3 1/4 to 3 1/2 inches wide). Cut off any extra dough, poke the bottoms with a fork, and set them on a baking tray covered with parchment.
03 -
Pop the empty shells into a 350°F oven for about 15–20 minutes until they turn a nice golden color. Keep an eye on them so they don't burn. Let them cool completely on a wire rack when done.
04 -
Put the walnut halves in a 350°F oven for a few minutes to toast them up. Roughly chop most of them, but save a few bigger pieces for later.
05 -
Put the white sugar in a pan over medium heat and let it melt until it turns a deep amber color. Add the diced salted butter and stir until it's all mixed in. Take it off the heat and mix in the whipping cream.
06 -
Mix the chopped walnuts into your caramel, making sure they're all coated well. Spoon this nutty caramel mix into your baked tartlet shells evenly. Let everything cool down before you serve them.