In a medium bowl, toss the chicken pieces with paprika, salt, and pepper until evenly coated.

Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat. Add the chicken in a single layer (work in batches if necessary to avoid crowding the pan). Cook for 3-4 minutes per side, until golden brown and cooked through. Remove the chicken from the skillet and set aside on a plate.

Reduce the heat to medium. Add the remaining 1 tablespoon of olive oil and the butter to the same skillet. Once the butter is melted, add the chopped onion and cook for 4-5 minutes, until softened and translucent.

Add the sliced mushrooms to the skillet. Cook, stirring occasionally, for 6-8 minutes, until they have released their moisture and started to brown. Stir in the minced garlic and cook for another minute until fragrant.

Sprinkle the flour over the vegetables and stir continuously for 1 minute to cook out the raw flour taste. This will form a thick paste.

If using, pour in the white wine to deglaze the pan, scraping up any browned bits from the bottom with a wooden spoon. Let it bubble and reduce for about 1 minute.

Gradually whisk in the chicken broth until smooth. Stir in the Dijon mustard and Worcestershire sauce. Bring the sauce to a gentle simmer and cook for 3-5 minutes, whisking occasionally, until it has thickened slightly.

Return the cooked chicken and any accumulated juices back to the skillet. Stir to combine and let it simmer gently for 2-3 minutes for the flavors to meld.

Remove the skillet from the heat. Let it cool for a minute, then stir in the room temperature sour cream until the sauce is smooth and creamy. Do not return the skillet to the heat, as this can cause the sour cream to curdle.

Taste and adjust seasoning with more salt and pepper if needed. Garnish with fresh parsley or dill and serve immediately over hot egg noodles, rice, or mashed potatoes.