Take butter, milk and eggs out of the refrigerator 30 minutes before starting.
To make the dough: In the bowl of a stand mixer, combine flour, instant yeast, sugar and salt. Add milk, eggs, egg yolks, vanilla and optional flavorings. Mix with dough hook on low speed until combined, about 2 minutes. With the mixer running, gradually add softened butter, piece by piece, waiting for each addition to be incorporated before adding more. Once all butter is added, knead for 8-10 minutes until the dough is smooth and elastic. Dough will be very soft and sticky — this is correct.
Place dough in a lightly greased bowl and cover with plastic wrap or clean kitchen towel. Let rise in a warm place (75°F) for 1-1.5 hours or until doubled. For easier handling, refrigerate dough for 30 minutes after rising.
To shape and arrange: First choose your pan setup:12×12- or 13×13-inch square cake pan (ideal), or half sheet pan with foil walls (you’ll need to create a 12×12-inch space by folding heavy-duty foil into 3-inch-high strips to form a square border inside your pan). Line your pan with parchment paper. With lightly oiled hands, divide dough into 16 pieces (74 g each). Roll each piece into a smooth ball. Arrange in a 4×4 grid with even spacing — they should be close enough to touch when fully risen. The foil walls or pan sides will help them rise upward instead of outward, creating perfectly fluffy, pull-apart sufganiyot. Cover loosely and let rise for 45-60 minutes until puffy. The balls should be touching and fill the space completely.
Preheat the oven to 350°F (180°C).
Gently brush risen dough with egg wash. Bake 20-25 minutes until golden brown and internal temperature reaches 190°F.
Let cool slightly for 5 minutes. Cut a small slit on each sufganiya, pipe in about 1 teaspoon of jam. Dust generously with powdered sugar. Best served warm.
