Make the crust:
In a food processor, pulse the nuts and sugar until finely chopped, 12 to 15 one-second pulses. Be careful not to overprocess; you want to keep some of the crunchy nut texture. Add the flour and 1/4 tsp. salt and pulse to combine. Add the butter and pulse just until the dough resembles coarse sand and starts to gather into clumps, about 8 one-second pulses. Drizzle the egg evenly over the mixture and pulse just until blended in, 5 to 6 one-second pulses. Do not overmix.
Turn the dough out onto a piece of plastic wrap and shape it into a disk (it will be very sticky). Wrap it tightly and chill for at least 2 hours or overnight.
Using your fingers, press the dough evenly into the bottom (not the sides) of a 9-1/2-inch fluted tart pan with a removable bottom. If the dough sticks to your fingers, dip them in water. Freeze the crust for 20 minutes.
Make the filling:
In a food processor, grind the macadamia nuts until they resemble coarse sand. Add the remaining filling ingredients and process until completely smooth, about 2 minutes.
Top and bake the tart:
Position a rack in the center of the oven and heat the oven to 375°F.
Using a small offset spatula, spread the filling over the bottom of the tart shell, leaving a 1/4-inch border, and then sprinkle with the flour. Working from the outside in and leaving a 1/4-inch border, arrange the pineapple tightly in overlapping concentric circles over the filling. (Each circle should overlap the
previous circle by 1/2 inch.) Use larger pieces of pineapple for the outer
circles and smaller pieces as you work your way toward the center. If
necessary, trim pieces to fit. You may not need all of the pineapple,
but it’s better to use more rather than less, since it will shrink as it
Bake the tart, rotating the pan after 20 minutes, until the crust is light golden-brown, 30 to 35 minutes. If the edges brown too quickly, cover them with foil.
Meanwhile, combine the honey and rum in a small saucepan. Cook over medium-high heat until just slightly reduced, 1 to 2 minutes. Remove from the heat.
Brush half of the honey syrup over the pineapple topping, taking care not to move the pineapple slices. Continue to bake the tart until the crust is deep golden-brown, 5 to 15 minutes more.
Transfer the tart to a rack and brush a bit more syrup on the top (you may not use it all). It’s OK if the tart looks liquidy in the center; it will thicken and firm up as it cools. Let cool completely and serve.
The tart can be made 1 day ahead. Cover it with plastic wrap and store at room temperature.