Preheat the oven to 325 degrees F. Lightly butter or oil a 4-cup glass loaf pan. Line the bottom and ends of the pan with parchment paper.
Put the ricotta, sour cream, sugar, milk, lemon zest, flour, eggs and egg yolks and salt in a food processor and process until smooth, about 1 minute. Pour into the prepared loaf pan. Bake until just set and barely golden, about 40 minutes. Turn the oven off and let the ricotta cool in the oven for 10 minutes, then cool completely in the pan on a wire rack. Refrigerate for at least 2 hours or up to overnight.
For the sauce:
Put the grapes, grape juice, honey, vanilla and salt in a saucepan. Cook over medium-high heat until the grapes burst and the juice thickens, about 10 minutes. Remove from the heat and stir in the lemon juice and zest.
Lift the baked ricotta with the parchment paper and set on a platter; discard the paper. Spoon the warm or room temperature grapes on top. Serve.
Copyright 2016 Television Food Network, G.P. All rights reserved.