Preheat the oven to 375 degrees. Evenly spread the nuts out on a large baking sheet and roast them in the oven for 8 minutes. Remove and set aside.

To make the crust, mix together all of the dry ingredients in a large bowl. Cut the butter over the bowl into roughly pea-sized pieces. Stir the mixture, then add the egg and beat the crust with an electric mixture using the dough attachment until a nice and smooth dough forms. Place the dough in the refrigerator for 30 minutes to get it to harden up a bit.

Then remove the dough from the refrigerator and press it into a well-greased 9-inch tart pan. Poke a few holes in the bottom of the tart with a fork, and then place in the oven to bake for 30 minutes, peeking at it every 5 minutes to vigorously poke any air bubbles that may be forming underneath the crust with your fork. If you notice the edges of the crust are browning more quickly than the base of the crust, wrap some tin foil around the crust's edge and place it back in the oven. The crust will be finished when you notice that the base of the crust is just starting to have the slightest golden tinge on some of the more raised areas. Remove the crust from the oven and allow it to cool completely before removing the sides of the tart pan.

To make the filling, heat the sugar in a medium-sized saucepan over medium-high heat, stirring constantly. The sugar will begin to melt, once it is completely melted and begins to boil, stop stirring. It should be a nice deep caramel color. Add the butter and stand back a bit as the caramel will hiss. Stir quickly until all of the butter is melted and fully incorporated into the melted sugar. Remove the pan from the heat, set it on a cool surface (like a hot plate you've just removed from the refrigerator), and add the heavy cream, whisking until a nice smooth caramel sauce forms. Add the disaronno and whisk until fully incorporated. Stop whisking and allow the caramel to cool to room temperature. Then stir in the salt.

To assemble your tart, evenly space about half of the nuts on top of the crust. Pour the cooled salted caramel sauce into the crust over the nuts, leaving about an inch of space between the caramel and the top of the crust. Sprinkle the remaining nuts onto the tart. Wait a few minutes for the caramel level to rise, and add more caramel sauce if necessary until the sauce is about 1/4 inch from the top of the crust. Store the tart in the refrigerator until you are ready to serve it. Reserve the remaining salted caramel sauce to drizzle over your dessert of choice!