A simple, strong espresso, without any milk or sugar, completes this dessert superb.
Peel rhubarb, cut in halves, then dice. Add some of the raspberry purée to a saucepan and bring to a simmer on medium heat. Add rhubarb, season with sugar, then set aside.
Preheat oven to 60°C/140°F. Beat egg white in a mixing bowl until stiff. Transfer to a piping bag and pipe small rounds onto a parchment-lined baking sheet. Bake for approx. 15 – 20 min.
In a nonstick pan, caramelize salty pretzels with sugar over medium heat; be careful not to let sugar burn. Remove from heat and let cool. Remove caramelized pretzels from pan and roughly chop.
Grate lime peel. Cover a microwave-safe plate with plastic wrap and transfer lime peel on top. Microwave on high for approx. 10 – 15 sec. Set aside.
Combine mascarpone with remaining raspberry purée and sugar until smooth.
Cut raspberries in halves for serving. Place a cake ring on a plate. Fill ring with a few spoonfuls of raspberry-rhubarb compote. Top with raspberry halves, caramelized pretzels, and some meringues. Remove cake ring. Form quenelle out of mascarpone using two spoons and place on the plate. Garnish with lime zest on top. Enjoy!