1 teaspoon vegetable oil
3 1/2 tablespoons salted butter, divided
2 (12-ounce) boneless cured ham steaks
1/4 cup Madeira
1 cup unsalted chicken stock
4 ounces fresh button or wild mushrooms, thinly sliced
1 tablespoon finely chopped shallots
1/4 cup heavy cream
Heat oil and 1 1/2 tablespoons butter in a large skillet over medium-high. Add 1 ham steak to skillet, and cook until browned, about 2 minutes per side. Remove from skillet, and repeat procedure with remaining ham steak.
Return steaks to skillet. Add Madeira, and cook, stirring occasionally, 1 minute. Add stock, mushrooms, and shallots to skillet; cook, periodically spooning cooking liquid over steaks, until mushrooms are tender, about 8 minutes. Remove ham and mushrooms with a slotted spoon; set aside.
Add peas, if using, and heavy cream to skillet. Stir and continue cooking until mixture is thickened, 4 to 5 minutes. Remove from heat, and stir in remaining 2 tablespoons butter until blended. Cut ham into 8 equal pieces; serve sauce and mushrooms over ham.