In Season 2, Episode 8 titled Full Leather Jacket of The Sopranos, Carmela is wanting Meadow to go to Georgetown University so that she will stay close to home.
Carmela realizes that her neighbor's sister is a prominent Georgetown alumni and wants her to give Meadow a reference. According to the Wikipedia page for this episode, Carmela is implicitly threatening Joan.
When Jeannie fails to persuade Joan to write a letter of recommendation for Meadow, Carmela presents Joan with a ricotta pie and a folder of Meadow's high school transcripts. When Joan refuses to write the letter, Carmela implicitly threatens her. Later, Jeannie informs Carmela that Joan has caved and agreed to write the letter.
Joan accuses Carmela of threatening her in the scene, but I am not understanding how she is threatening her.
How exactly did Carmela threaten Joan? What am I missing in this scene to see any threats being made?