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.