Combine raspberries, honey, lemon juice, and salt in a large saucepan. Warm over medium-high heat, stirring often, until the mixture boils. Once boiling, reduce to a simmer and cook until thickened, about 20 minutes.
Remove the jam from the heat and stir in vanilla bean paste (see note). Allow jam to cool while you prepare the rest of the recipe. Jam can be made ahead of time and stored in the refrigerator.
For Crusts:
In a small bowl combine cake flour, ground pistachios, and salt. Stir to combine. Set aside.
In the bowl of a stand mixer, beat butter and sugar until light and fluffy. Add egg and vanilla bean paste (see note) and beat to combine.
With the mixer on low speed, gradually add the flour mixture. Mix until just combined.
Turn dough out onto a lightly floured surface and knead slightly to form a disc. Wrap the disc in plastic and freeze 20 minutes. Grease 24 teeny 2.5" tartlet pans (see note) and set aside.
After chilling, roll the dough out on a lightly floured surface to about ⅛" thick. Line each of the pans with the pastry, taking care not to stretch the dough as you do so. (Pastry scraps may be gathered and re-rolled as needed.) Place crusts on a baking sheet and freeze 10 minutes.
Preheat oven to 350° F. Leaving the tartlets on the baking sheet, bake 10-15 minutes. Pastry will appear dry and very slightly browned. Allow crusts to cool completely.
For Meringue:
In a large heatproof bowl, combine egg whites, honey, sugar, and salt. Whisk to combine.
Place the bowl over a saucepan of simmering water, taking care that the water doesn't touch the bowl. Whisking constantly, warm the mixture to 160° F, about 8-10 minutes.
Transfer the mixture to the bowl of a stand mixer and whip using the whisk attachment until it reaches medium-stiff peaks. Add vanilla bean paste (see note) and beat to incorporate.
For Assembly:
Fill the cooled tartlets with the raspberry jam. I used about 2 tablespoons of jam per tartlet. Spoon or pipe meringue on top of each tartlet. Toast the meringue, if desired (see note). Garnish as desired; I topped mine each with a raspberry and chopped pistachios.Enjoy!
Notes
Note on vanilla bean paste: It's no secret that I LOVE this ingredient! Easier/cheaper than buying whole beans and tastier than extract (or at least I think so)! If you don't have vanilla bean paste, you can find it here. If you prefer to substitute, you can use an equal measure of vanilla extract.
Note on cake flour: If you don't see it locally, you can find it here. You can substitute the cake flour with all-purpose flour if that's all you have on-hand, but the crust won't be as tender!
Note on tartlet pans: I used 24 (ridiculously tiny) 2.5" tartlet pans (like these here). You may end up with more jam and pastry than you need, but you could easily make a 9" round tart with this same recipe, just increase the chill time and bake time on the tart (25-30 minutes).
Note on toasting meringue: I use a kitchen torch to toast my meringue. If you don't have a torch, you can put the tartlets under the broiler, just don't take your eyes off them for a second! I prefer the torch, since it gives more control over the toasting. My torch is old, so I don't even know what kind it is, but this one (link here) has great reviews.