Beat the butter and powdered sugar in the bowl of a stand mixer until creamy.
Beat in the egg yolk and mix until fully combined.
With the mixer on low speed, beat in the salt and flour just until the dough comes together and there is no more visible flour. Careful not to over-mix. Remove dough from the bowl and press the dough into the tart pan, making sure it is evenly distributed. Using a fork, prick the bottom of the tart shell to prevent the bottom from puffing up when baking.
Wrap the pan loosely in plastic and chill 30 minutes.
Bake the tart shell at 400F until the crust is golden, approximately 10 minutes. You do not want the shell to be too brown. Remove carefully from oven and let rest on a wire rack.
Strawberry Rhubarb Compote
In a heavy medium saucepan over medium heat, melt the butter.
When the butter has melted, add the remaining ingredients to the pan. Allow to cook, undisturbed, for 2 minutes.
Gently stir and continue to cook, stirring occasionally, until the rhubarb is tender and juices become thick (10 to 15 minutes).
Remove from heat and let compote cool.
Almond Frangipane Filling
Beat together sugar and butter until creamy. Add eggs, one at a time, and mix until well-incorporated. Add vanilla.
In a separate bowl, whisk together ground almonds, flour, baking powder, and salt.
Add dry mixture to butter-sugar mixture and mix until combined.
Preheat oven to 350F
In a large bowl, toss together rhubarb, sugar, and vanilla. Set aside for 15 minutes.
Transfer mixture to a parchment lined baking tray and bake for 20 minutes, until rhubarb is tender to the fork.
Remove from oven and let rhubarb cool.
Preheat oven to 350F.
Evenly spread compote on cooked tart shell.
Carefully spoon the almond frangipane mixture on top of rhubarb compote layer. Even out layer with the back of a spoon or an offset spatula.
Place stalks of rhubarb in a radial pattern on top of almond filling.
Bake tart for 40 - 45 minutes until tart is golden. Let tart cool in tart pan for 15 minutes before carefully removing.