Step 1

Combine rhubarb, 1/2 cup sugar, and salt in a saucepan. Bring to a simmer over medium heat. Cook until rhubarb has broken down and mixture has thickened, stirring occasionally, 8 to 10 minutes. Remove from heat and stir in lemon juice. Place mixture into a heat-safe bowl and place into the refrigerator to cool.

Step 2

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 10-cup Bundt® pan.

Step 3

Whisk flour, baking powder, salt, and baking soda together in a small bowl.

Step 4

Cream butter, oil, and sugar together with an electric mixer in a large bowl until light and fluffy, about 3 minutes. Add in eggs, 1 at a time, mixing well after each addition. Beat mixture for another 3 minutes on medium-high speed until batter has lightened in color. Mix in vanilla and almond extracts. Add in half of the flour mixture and mix until just combined. Pour in buttermilk and mix until just combined. Add in remaining flour mixture and mix until just combined. Do not overmix.

Step 5

Pour half of the batter into the prepared Bundt® pan and smooth into an even layer. Remove rhubarb jam from fridge, and carefully spoon over the batter. Place dollops of remaining batter over the jam, and gently smooth into an even layer; taking care to cover the jam completely.

Step 6

Place pan into preheated oven and bake until a bamboo skewer inserted into the center of the cake comes out with just a few moist crumbs, 55 to 60 minutes. Cool cake in pan for 30 minutes before gently running a knife around the edges to loosen. Invert cake onto a wire rack and cool completely.