Heat lemon juice in a small saucepan over medium, stirring occasionally, until reduced by half, about 8 minutes. Remove from heat; add cream, pepper, and 2 tablespoons butter, stirring until combined. Season with salt to taste. Set aside.

While lemon juice is reducing, bring stock to a simmer in a large saucepan over medium-high. Turn off heat, and set aside.

Heat oil and remaining 1 tablespoon butter in a second large saucepan over medium. Add onion and shallot; cook, stirring occasionally, until soft and translucent (no browning), about 6 minutes.

Add rice; cook, stirring constantly, until every grain is coated in fat, 1 to 2 minutes.

Add wine, stirring constantly until the liquid is au sec, about 30 seconds.

Add 4 cups hot stock, about ¼ cup at a time, to rice mixture, stirring constantly over medium. Let each addition cook down until almost absorbed before adding the next. Continue for 30 to 35 minutes total, adding up to remaining 1 cup hot stock, as needed, until rice is creamy and tender but not mushy.

Reduce heat to low; fold in lemony cream sauce, stirring constantly until fully combined.

Take saucepan off heat, and fold Parmigiano-Reggiano into risotto until combined and melted. Season with additional salt to taste.

Spoon risotto onto a plate; tap bottom of plate so risotto spreads out slightly. Serve immediately with additional pepper, oil, and Parmigiano-Reggiano.