How to Make the Ultimate Umami-Bomb Vegetarian Demi-Glace
1 quart strawberries, hulled and quartered
1 pound rhubarb, sliced 1/4 inch thick
1/4 cup sugar
2 tablespoons cornstarch
1 teaspoon pure vanilla extract
Pinch of salt
1/2 cup sliced almonds
3/4 cup all-purpose flour
1/4 teaspoon baking soda
1/4 teaspoon salt
1 stick unsalted butter, softened
1/4 cup granulated sugar
1/4 cup light brown sugar
1 large egg yolk, at room temperature
1/4 teaspoon pure vanilla extract
Make the filling
Preheat the oven to 350°. In a large bowl, toss the strawberries and rhubarb with the sugar, cornstarch, vanilla and salt. Let stand at room temperature for 30 minutes, tossing occasionally.
Make the topping
Spread the almonds in a 9-inch pie plate and toast, stirring once, until golden and fragrant, about 7 minutes. Let cool completely.
In a food processor, pulse the almonds with the flour, baking soda and salt until the almonds are coarsely ground. In the bowl of a stand mixer fitted with the paddle, cream the butter with both sugars until fluffy, about 3 minutes. Scrape down the side of the bowl. Add the egg yolk and vanilla and beat at medium-high speed for 2 minutes. Scrape down the bowl again. Add the almond-flour mixture all at once and mix at low speed just until incorporated.
Pour the fruit into the pie plate. Dollop teaspoon-size clumps of the batter over the fruit. Bake until the topping is deeply browned and the juices bubbling up around it appear thickened, about 45 minutes. Let cool slightly; serve warm.