Oyster and Spinach-stuffed Mushrooms

Prepare spinach according to package directions; drain and pat dry with paper towels. Set aside.

Remove stems from mushrooms, discarding stems.

Melt 2 tablespoons butter in a large skillet over medium-high heat.

Add 12 mushrooms; saut 4 minutes or until barely tender. Repeat procedure with remaining mushrooms and 2 tablespoons butter.

Remove from skillet, and place cap-side up in a 15- x 10-inch jelly-roll pan.

Place 1 oyster piece in each mushroom cap.

Melt remaining 2 tablespoons butter in a large skillet over medium-high heat.

Add artichoke and onion; saut 3 to 4 minutes or until tender.

Remove from heat, and stir in reserved spinach, sour cream, 1/3 cup cheese, and salt. Spoon mixture evenly into mushroom caps; sprinkle with remaining cheese and crumbled bacon.

Bake at 350 for 20 minutes or until thoroughly heated.