Dissolve yeast in warm water with 2 tablespoons all-purpose flour; let rest 5 minutes. Add molasses and 1 cup rye flour, mix, and rest 1-2 hours until foamy.
Combine remaining rye flour, all-purpose flour, caraway, dill, and salt in a bowl. Add starter mixture and 1/2 cup warm water; mix until no dry flour remains.
Knead dough 8-10 minutes until smooth and elastic. Let rest 30 minutes, then knead again 3-4 minutes.
Shape into 2 loaves and place in floured bowls. Cover and let ferment 2 more hours until doubled in size.
Preheat oven to 375°F (190°C). Score loaves and bake 25 minutes. Rotate and bake 15 more minutes with a Dutch oven (optional) for crisp crust.
Notes
Use a Dutch oven for crisper crust. If time-sensitive, let ferment at warm room temperature (75°F/24°C). Store in a paper bag for 1-2 days, or freeze for longer storage.