Dice Shallot:
Halve the shallot, remove the peel, and dice it finely.Mince Garlic:
Peel the garlic cloves and mince them finely.Cut Mushrooms:
Rinse the mushrooms; cut any that are bigger than a single bite into halves or quarters.Trim Chicken Livers:
Prepare the chicken livers by trimming off sinew and cutting into 3/4-1 inch (2-2.5 cm) chunks.Cook Shallot in Butter:
Set a 12-inch (30 cm) skillet over medium-high heat and melt the butter. Once it starts foaming, add the diced shallot and cook for 2 minutes, stirring now and then, without letting it brown.Cook Garlic:
Add the minced garlic and cook for 1 minute while stirring.Sauté Mushrooms:
Add the mushrooms, season with salt and pepper, and cook for 2-3 minutes, stirring from time to time.Cook Livers with Tomato Paste:
Raise the heat to high, stir in the tomato paste and chicken liver pieces, and cook for 2-3 minutes.Reduce Red Wine:
Pour in the red wine and let it reduce by half, which takes about 3-4 minutes.Make Cornstarch Slurry:
Combine 1 tablespoon water with the cornstarch to create a slurry.Add Peas and Slurry:
Lower the heat to medium. Put the frozen peas and the cornstarch slurry into the pan and cook for 1-2 minutes, stirring constantly.